--- /dev/null
+/*
+ * Generic MODBUS Library for STM32
+ *
+ * (c) 2019 Martin Mareš <mj@ucw.cz>
+ */
+
+#include "util.h"
+#include "modbus.h"
+
+#include <stddef.h>
+#include <string.h>
+
+#include <libopencm3/cm3/nvic.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/usart.h>
+#include <libopencm3/stm32/timer.h>
+
+/*** Configuration ***/
+
+// You should set the following parameters in config.h
+
+// USART (pins are expected to be configured by the caller)
+// #define MODBUS_USART USART2
+// #define MODBUS_NVIC_USART_IRQ NVIC_USART2_IRQ
+// #define MODBUS_USART_ISR usart2_isr
+
+// GPIO pin for transmitter enable (pins is expected to be configured by the caller)
+// #define MODBUS_TXEN_GPIO_PORT GPIOA
+// #define MODBUS_TXEN_GPIO_PIN GPIO1
+
+// Timer
+// #define MODBUS_TIMER TIM2
+// #define MODBUS_NVIC_TIMER_IRQ NVIC_TIM2_IRQ
+// #define MODBUS_TIMER_ISR tim2_isr
+
+// Slave address we are responding at
+// #define MODBUS_OUR_ADDRESS 42
+
+// Baud rate
+#ifndef MODBUS_BAUD_RATE
+#define MODBUS_BAUD_RATE 19200
+#endif
+
+// CPU clock frequency
+// #define CPU_CLOCK_MHZ 72
+
+// Receive buffer size (standard specifies 256 bytes, you can make it shorter if necessary)
+#ifndef MODBUS_RX_BUFSIZE
+#define MODBUS_RX_BUFSIZE 256
+#endif
+
+// Transmit buffer size (standard specifies 256 bytes, you can make it shorter if necessary)
+#ifndef MODBUS_TX_BUFSIZE
+#define MODBUS_TX_BUFSIZE 256
+#endif
+
+// Receive timeout in microseconds
+#ifndef MODBUS_RX_TIMEOUT
+#if MODBUS_BAUD_RATE <= 19200
+// For low baud rates, the standard specifies timeout of 1.5 character times
+// (1 character = start bit + 8 data bits + parity bit + stop bit = 11 bits)
+#define MODBUS_RX_TIMEOUT (1000000*11*3/2/MODBUS_BAUD_RATE)
+#else
+// For high rates, the timeout is fixed to 750 μs
+#define MODBUS_RX_TIMEOUT 750
+#endif
+#endif
+
+/*** State ***/
+
+enum mb_state {
+ STATE_RX,
+ STATE_RX_DONE,
+ STATE_PROCESSING,
+ STATE_TX,
+ STATE_TX_LAST,
+ STATE_TX_DONE,
+};
+
+static byte rx_buf[MODBUS_RX_BUFSIZE];
+static u16 rx_size;
+static byte rx_bad;
+static byte state; // STATE_xxx
+
+static byte *rx_frame;
+static byte *rx_frame_end;
+
+static byte tx_buf[MODBUS_TX_BUFSIZE];
+static u16 tx_size;
+static u16 tx_pos;
+
+static bool check_frame(void);
+static void process_frame(void);
+
+/*** Low-level layer ***/
+
+static void rx_init(void)
+{
+ state = STATE_RX;
+ rx_size = 0;
+ rx_bad = 0;
+ usart_set_mode(MODBUS_USART, USART_MODE_RX);
+ usart_enable_rx_interrupt(MODBUS_USART);
+}
+
+static void rx_done(void)
+{
+ state = STATE_RX_DONE;
+ usart_disable_rx_interrupt(MODBUS_USART);
+}
+
+static void tx_init(void)
+{
+ state = STATE_TX;
+ tx_pos = 0;
+ gpio_set(MODBUS_TXEN_GPIO_PORT, MODBUS_TXEN_GPIO_PIN);
+ usart_set_mode(MODBUS_USART, USART_MODE_TX);
+ usart_enable_tx_interrupt(MODBUS_USART);
+}
+
+static void tx_done(void)
+{
+ state = STATE_TX_DONE;
+ // usart_disable_tx_interrupt(MODBUS_USART); // Already done by irq handler
+ gpio_clear(MODBUS_TXEN_GPIO_PORT, MODBUS_TXEN_GPIO_PIN);
+}
+
+void modbus_init(void)
+{
+ timer_set_prescaler(MODBUS_TIMER, CPU_CLOCK_MHZ-1); // 1 tick = 1 μs
+ timer_set_mode(MODBUS_TIMER, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_DOWN);
+ timer_update_on_overflow(MODBUS_TIMER);
+ timer_disable_preload(MODBUS_TIMER);
+ timer_one_shot_mode(MODBUS_TIMER);
+ timer_enable_irq(MODBUS_TIMER, TIM_DIER_UIE);
+ nvic_enable_irq(MODBUS_NVIC_TIMER_IRQ);
+
+ gpio_clear(MODBUS_TXEN_GPIO_PORT, MODBUS_TXEN_GPIO_PIN);
+
+ usart_set_baudrate(MODBUS_USART, MODBUS_BAUD_RATE);
+ usart_set_databits(MODBUS_USART, 9);
+ usart_set_stopbits(MODBUS_USART, USART_STOPBITS_1);
+ usart_set_parity(MODBUS_USART, USART_PARITY_EVEN);
+ usart_set_flow_control(MODBUS_USART, USART_FLOWCONTROL_NONE);
+
+ rx_init();
+
+ nvic_enable_irq(MODBUS_NVIC_USART_IRQ);
+ usart_enable(MODBUS_USART);
+}
+
+void MODBUS_USART_ISR(void)
+{
+ u32 status = USART_SR(MODBUS_USART);
+
+ if (status & USART_SR_RXNE) {
+ uint ch = usart_recv(MODBUS_USART);
+ if (state == STATE_RX) {
+ if (status & (USART_SR_FE | USART_SR_ORE | USART_SR_NE)) {
+ rx_bad = 1;
+ } else if (rx_size < MODBUS_RX_BUFSIZE) {
+ rx_buf[rx_size++] = ch;
+ } else {
+ // Frame too long
+ rx_bad = 2;
+ }
+ timer_set_period(MODBUS_TIMER, MODBUS_RX_TIMEOUT);
+ timer_generate_event(MODBUS_TIMER, TIM_EGR_UG);
+ timer_enable_counter(MODBUS_TIMER);
+ }
+ }
+
+ if (state == STATE_TX) {
+ if (status & USART_SR_TXE) {
+ if (tx_pos < tx_size) {
+ usart_send(MODBUS_USART, tx_buf[tx_pos++]);
+ } else {
+ // The transmitter is double-buffered, so at this moment, it is transmitting
+ // the last byte of the frame. Wait until transfer is completed.
+ usart_disable_tx_interrupt(MODBUS_USART);
+ USART_CR1(MODBUS_USART) |= USART_CR1_TCIE;
+ state = STATE_TX_LAST;
+ }
+ }
+ } else if (state == STATE_TX_LAST) {
+ if (status & USART_SR_TC) {
+ // Transfer of the last byte is complete. Release the bus.
+ USART_CR1(MODBUS_USART) &= ~USART_CR1_TCIE;
+ tx_done();
+ rx_init();
+ }
+ }
+}
+
+void MODBUS_TIMER_ISR(void)
+{
+ if (TIM_SR(MODBUS_TIMER) & TIM_SR_UIF) {
+ TIM_SR(MODBUS_TIMER) &= ~TIM_SR_UIF;
+ if (state == STATE_RX)
+ rx_done();
+ }
+}
+
+void modbus_loop(void)
+{
+ if (state != STATE_RX_DONE)
+ return;
+ state = STATE_PROCESSING;
+
+ if (!check_frame()) {
+ rx_init();
+ return;
+ }
+
+ if (rx_buf[0] == MODBUS_OUR_ADDRESS) {
+ // Frame addressed to us: process and reply
+ process_frame();
+ tx_init();
+ } else if (rx_buf[0] == 0x00) {
+ // Broadcast frame: process, but do not reply
+ process_frame();
+ rx_init();
+ } else {
+ // Somebody else's frame: discard
+ rx_init();
+ }
+}
+
+/** CRC ***/
+
+static const byte crc_hi[] = {
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
+ 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
+ 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40,
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
+ 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41,
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
+ 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40,
+ 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
+ 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40,
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40,
+ 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
+ 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40,
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
+ 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
+ 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40,
+ 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
+ 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
+ 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
+ 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40
+};
+
+static const byte crc_lo[] = {
+ 0x00, 0xc0, 0xc1, 0x01, 0xc3, 0x03, 0x02, 0xc2, 0xc6, 0x06,
+ 0x07, 0xc7, 0x05, 0xc5, 0xc4, 0x04, 0xcc, 0x0c, 0x0d, 0xcd,
+ 0x0f, 0xcf, 0xce, 0x0e, 0x0a, 0xca, 0xcb, 0x0b, 0xc9, 0x09,
+ 0x08, 0xc8, 0xd8, 0x18, 0x19, 0xd9, 0x1b, 0xdb, 0xda, 0x1a,
+ 0x1e, 0xde, 0xdf, 0x1f, 0xdd, 0x1d, 0x1c, 0xdc, 0x14, 0xd4,
+ 0xd5, 0x15, 0xd7, 0x17, 0x16, 0xd6, 0xd2, 0x12, 0x13, 0xd3,
+ 0x11, 0xd1, 0xd0, 0x10, 0xf0, 0x30, 0x31, 0xf1, 0x33, 0xf3,
+ 0xf2, 0x32, 0x36, 0xf6, 0xf7, 0x37, 0xf5, 0x35, 0x34, 0xf4,
+ 0x3c, 0xfc, 0xfd, 0x3d, 0xff, 0x3f, 0x3e, 0xfe, 0xfa, 0x3a,
+ 0x3b, 0xfb, 0x39, 0xf9, 0xf8, 0x38, 0x28, 0xe8, 0xe9, 0x29,
+ 0xeb, 0x2b, 0x2a, 0xea, 0xee, 0x2e, 0x2f, 0xef, 0x2d, 0xed,
+ 0xec, 0x2c, 0xe4, 0x24, 0x25, 0xe5, 0x27, 0xe7, 0xe6, 0x26,
+ 0x22, 0xe2, 0xe3, 0x23, 0xe1, 0x21, 0x20, 0xe0, 0xa0, 0x60,
+ 0x61, 0xa1, 0x63, 0xa3, 0xa2, 0x62, 0x66, 0xa6, 0xa7, 0x67,
+ 0xa5, 0x65, 0x64, 0xa4, 0x6c, 0xac, 0xad, 0x6d, 0xaf, 0x6f,
+ 0x6e, 0xae, 0xaa, 0x6a, 0x6b, 0xab, 0x69, 0xa9, 0xa8, 0x68,
+ 0x78, 0xb8, 0xb9, 0x79, 0xbb, 0x7b, 0x7a, 0xba, 0xbe, 0x7e,
+ 0x7f, 0xbf, 0x7d, 0xbd, 0xbc, 0x7c, 0xb4, 0x74, 0x75, 0xb5,
+ 0x77, 0xb7, 0xb6, 0x76, 0x72, 0xb2, 0xb3, 0x73, 0xb1, 0x71,
+ 0x70, 0xb0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
+ 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9c, 0x5c,
+ 0x5d, 0x9d, 0x5f, 0x9f, 0x9e, 0x5e, 0x5a, 0x9a, 0x9b, 0x5b,
+ 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4b, 0x8b,
+ 0x8a, 0x4a, 0x4e, 0x8e, 0x8f, 0x4f, 0x8d, 0x4d, 0x4c, 0x8c,
+ 0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
+ 0x43, 0x83, 0x41, 0x81, 0x80, 0x40
+};
+
+static u16 crc16(byte *buf, u16 len)
+{
+ byte hi = 0xff, lo = 0xff;
+
+ while (len--) {
+ byte i = hi ^ *buf++;
+ hi = lo ^ crc_hi[i];
+ lo = crc_lo[i];
+ }
+
+ return (hi << 8 | lo);
+}
+
+/*** High-level layer ***/
+
+static bool check_frame(void)
+{
+ if (rx_bad) {
+ // FIXME: Error counters?
+ return false;
+ }
+
+ if (rx_size < 4) {
+ // FIXME: Error counters?
+ return false;
+ }
+
+ u16 crc = crc16(rx_buf, rx_size - 2);
+ u16 rx_crc = (rx_buf[rx_size-2] << 8) | rx_buf[rx_size-1];
+ if (crc != rx_crc) {
+ // FIXME: Error counters?
+ return false;
+ }
+
+ rx_frame = rx_buf + 1;
+ rx_frame_end = rx_frame + rx_size - 2;
+ return true;
+}
+
+enum mb_function {
+ FUNC_READ_COILS = 0x01,
+ FUNC_READ_DISCRETE_INPUTS = 0x02,
+ FUNC_READ_HOLDING_REGISTERS = 0x03,
+ FUNC_READ_INPUT_REGISTERS = 0x04,
+ FUNC_WRITE_SINGLE_COIL = 0x05,
+ FUNC_WRITE_SINGLE_REGISTER = 0x06,
+ FUNC_READ_EXCEPTION_STATUS = 0x07,
+ FUNC_DIAGNOSTICS = 0x08,
+ FUNC_GET_COMM_EVENT_COUNTER = 0x0b,
+ FUNC_GET_COMM_EVENT_LOG = 0x0c,
+ FUNC_WRITE_MULTIPLE_COILS = 0x0f,
+ FUNC_WRITE_MULTIPLE_REGISTERS = 0x10,
+ FUNC_REPORT_SLAVE_ID = 0x11,
+ FUNC_READ_FILE_RECORD = 0x14,
+ FUNC_WRITE_FILE_RECORD = 0x15,
+ FUNC_MASK_WRITE_REGISTER = 0x16,
+ FUNC_READ_WRITE_MULTIPLE_REGISTERS = 0x17,
+ FUNC_READ_FIFO_QUEUE = 0x18,
+ FUNC_ENCAPSULATED_INTERFACE_TRANSPORT = 0x2b,
+};
+
+enum mb_error {
+ ERR_ILLEGAL_FUNCTION = 0x01,
+ ERR_ILLEGAL_DATA_ADDRESS = 0x02,
+ ERR_ILLEGAL_DATA_VALUE = 0x03,
+};
+
+static uint read_remains(void)
+{
+ return rx_frame_end - rx_frame;
+}
+
+static byte read_byte(void)
+{
+ return *rx_frame++;
+}
+
+static u16 read_u16(void)
+{
+ byte hi = *rx_frame++;
+ byte lo = *rx_frame++;
+ return (hi << 8) | lo;
+}
+
+static void write_byte(byte v)
+{
+ tx_buf[tx_size++] = v;
+}
+
+static void write_u16(u16 v)
+{
+ write_byte(v >> 8);
+ write_byte(v);
+}
+
+static bool body_fits(uint body_len)
+{
+ // body_len excludes slave address, function code, and CRC
+ return (2 + body_len + 2 <= MODBUS_TX_BUFSIZE);
+}
+
+static void report_error(byte code)
+{
+ // Discard the partially constructed body of the reply and rewrite the header
+ tx_buf[1] |= 0x80;
+ tx_buf[2] = code;
+ tx_size = 3;
+}
+
+static void func_read_bits(bool coils)
+{
+ if (read_remains() < 4)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 start = read_u16();
+ u16 count = read_u16();
+
+ uint bytes = (count+7) / 8;
+ if (!body_fits(1 + bytes))
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ for (u16 i = 0; i < count; i++)
+ if (!(coils ? modbus_check_coil : modbus_check_discrete_input)(start + i))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ write_byte(bytes);
+ for (u16 i = 0; i < bytes; i++) {
+ byte b = 0;
+ for (byte j = 0; j < 8 && 8*i + j < count; j++) {
+ uint addr = start + 8*i + j;
+ if ((coils ? modbus_get_coil : modbus_get_discrete_input)(addr))
+ b |= 1 << j;
+ }
+ write_byte(b);
+ }
+}
+
+static void func_read_registers(byte holding)
+{
+ if (read_remains() < 4)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 start = read_u16();
+ u16 count = read_u16();
+
+ uint bytes = 2*count;
+ if (!body_fits(1 + bytes))
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ for (u16 i = 0; i < count; i++)
+ if (!(holding ? modbus_check_holding_register : modbus_check_input_register)(start + i))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ // FIXME: Reporting of slave failures?
+ write_byte(bytes);
+ for (u16 i = 0; i < count; i++)
+ write_u16((holding ? modbus_get_holding_register : modbus_get_input_register)(start + i));
+}
+
+static void func_write_single_coil(void)
+{
+ if (read_remains() < 4)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 addr = read_u16();
+ u16 value = read_u16();
+
+ if (!modbus_check_coil(addr))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+ if (value != 0x0000 && value != 0xff00)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ modbus_set_coil(addr, value);
+}
+
+static void func_write_single_register(void)
+{
+ if (read_remains() < 4)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 addr = read_u16();
+ u16 value = read_u16();
+
+ if (!modbus_check_holding_register(addr))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ modbus_set_holding_register(addr, value);
+}
+
+static void func_write_multiple_coils(void)
+{
+ if (read_remains() < 5)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 start = read_u16();
+ u16 count = read_u16();
+ byte bytes = read_byte();
+
+ if (read_remains() < bytes || bytes != (count+7) / 8)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ for (u16 i = 0; i < count; i++)
+ if (!modbus_check_coil(start + i))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ for (u16 i = 0; i < count; i++)
+ modbus_set_coil(start + i, rx_frame[i/8] & (1U << (i%8)));
+}
+
+static void func_write_multiple_registers(void)
+{
+ if (read_remains() < 5)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 start = read_u16();
+ u16 count = read_u16();
+ byte bytes = read_byte();
+
+ if (read_remains() < bytes || bytes != 2*count)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ for (u16 i = 0; i < count; i++)
+ if (!modbus_check_holding_register(start + i))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ for (u16 i = 0; i < count; i++)
+ modbus_set_holding_register(start + i, read_u16());
+}
+
+static void func_mask_write_register(void)
+{
+ if (read_remains() < 6)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 addr = read_u16();
+ u16 and_mask = read_u16();
+ u16 or_mask = read_u16();
+
+ if (!modbus_check_holding_register(addr))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ u16 reg = modbus_get_holding_register(addr);
+ reg = (reg & and_mask) | (or_mask & ~and_mask);
+ modbus_set_holding_register(addr, reg);
+}
+
+static void func_read_write_multiple_registers(void)
+{
+ if (read_remains() < 9)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ u16 read_start = read_u16();
+ u16 read_count = read_u16();
+ u16 write_start = read_u16();
+ u16 write_count = read_u16();
+ byte write_bytes = read_byte();
+
+ if (read_remains() < write_bytes || write_bytes != 2*write_count)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ for (u16 i = 0; i < read_count; i++)
+ if (!modbus_check_holding_register(read_start + i))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ for (u16 i = 0; i < write_count; i++)
+ if (!modbus_check_holding_register(write_start + i))
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+
+ byte read_bytes = 2*write_count;
+ if (!body_fits(1 + read_bytes))
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ for (u16 i = 0; i < write_count; i++)
+ modbus_set_holding_register(write_start + i, read_u16());
+
+ write_byte(read_bytes);
+ for (u16 i = 0; i < read_count; i++)
+ modbus_get_holding_register(read_start + i);
+}
+
+static void func_encapsulated_interface_transport(void)
+{
+ if (read_remains() < 3 ||
+ read_byte() != 0x0e)
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+
+ byte action = read_byte();
+ byte id = read_byte();
+
+ byte range_min, range_max;
+ switch (action) {
+ case 1:
+ // Streaming access to basic identification
+ range_min = MODBUS_ID_VENDOR_NAME;
+ range_max = MODBUS_ID_MAJOR_MINOR_REVISION;
+ break;
+ case 2:
+ // Streaming access to regular identification
+ range_min = MODBUS_ID_VENDOR_URL;
+ range_max = MODBUS_ID_USER_APP_NAME;
+ break;
+ case 4:
+ // Individual access
+ if (id >= MODBUS_ID_MAX || !modbus_id_strings[id])
+ return report_error(ERR_ILLEGAL_DATA_ADDRESS);
+ range_min = range_max = id;
+ break;
+ default:
+ return report_error(ERR_ILLEGAL_DATA_VALUE);
+ }
+
+ if (action != 4) {
+ if (id < range_min || id > range_max)
+ id = range_min;
+ }
+
+ write_byte(0x0e); // Repeat a part of the request
+ write_byte(action);
+
+ // Conformity level
+ if (modbus_id_strings[MODBUS_ID_VENDOR_URL] ||
+ modbus_id_strings[MODBUS_ID_PRODUCT_NAME] ||
+ modbus_id_strings[MODBUS_ID_USER_APP_NAME])
+ write_byte(0x82); // Regular identification, both stream and individual access supported
+ else
+ write_byte(0x81); // Basic identification only
+
+ u16 more_follows_at = tx_size;
+ write_byte(0); // More follows: so far not
+ write_byte(0); // Next object ID: so far none
+ write_byte(0); // Number of objects
+
+ for (id = range_min; id <= range_max; id++) {
+ if (modbus_id_strings[id]) {
+ byte len = strlen(modbus_id_strings[id]);
+ byte remains = MODBUS_TX_BUFSIZE - 4 - tx_size; // 2 for CRC, 2 for object header
+ if (len > remains) {
+ // If it is the only object, cut it
+ if (!tx_buf[more_follows_at + 2])
+ len = remains;
+ else {
+ // More follows, report the next ID
+ tx_buf[more_follows_at] = 0xff;
+ tx_buf[more_follows_at + 1] = id;
+ break;
+ }
+ }
+ tx_buf[more_follows_at + 2] ++;
+ write_byte(id);
+ write_byte(len);
+ memcpy(tx_buf + tx_size, modbus_id_strings[id], len);
+ tx_size += len;
+ }
+ }
+}
+
+static void process_frame(void)
+{
+ byte func = read_byte();
+
+ // Prepare reply frame
+ tx_buf[0] = MODBUS_OUR_ADDRESS;
+ tx_buf[1] = rx_buf[1];
+ tx_size = 2;
+
+ switch (func) {
+ case FUNC_READ_COILS:
+ func_read_bits(true);
+ break;
+ case FUNC_READ_DISCRETE_INPUTS:
+ func_read_bits(false);
+ break;
+ case FUNC_READ_HOLDING_REGISTERS:
+ func_read_registers(true);
+ break;
+ case FUNC_READ_INPUT_REGISTERS:
+ func_read_registers(false);
+ break;
+ case FUNC_WRITE_SINGLE_COIL:
+ func_write_single_coil();
+ break;
+ case FUNC_WRITE_SINGLE_REGISTER:
+ func_write_single_register();
+ break;
+ case FUNC_WRITE_MULTIPLE_COILS:
+ func_write_multiple_coils();
+ break;
+ case FUNC_WRITE_MULTIPLE_REGISTERS:
+ func_write_multiple_registers();
+ break;
+ case FUNC_MASK_WRITE_REGISTER:
+ func_mask_write_register();
+ break;
+ case FUNC_READ_WRITE_MULTIPLE_REGISTERS:
+ func_read_write_multiple_registers();
+ break;
+ case FUNC_ENCAPSULATED_INTERFACE_TRANSPORT:
+ func_encapsulated_interface_transport();
+ break;
+ default:
+ report_error(ERR_ILLEGAL_FUNCTION);
+ }
+
+ // Finish reply frame
+ write_u16(crc16(tx_buf, tx_size));
+}
--- /dev/null
+/*
+ * Generic MODBUS Library for STM32
+ *
+ * (c) 2019 Martin Mareš <mj@ucw.cz>
+ */
+
+#ifndef _MODBUS_H
+#define _MODBUS_H
+
+void modbus_init(void);
+void modbus_loop(void);
+
+// Callbacks
+
+bool modbus_check_discrete_input(u16 addr);
+bool modbus_get_discrete_input(u16 addr);
+
+bool modbus_check_coil(u16 addr);
+bool modbus_get_coil(u16 addr);
+void modbus_set_coil(u16 addr, bool value);
+
+bool modbus_check_input_register(u16 addr);
+u16 modbus_get_input_register(u16 addr);
+
+bool modbus_check_holding_register(u16 addr);
+u16 modbus_get_holding_register(u16 addr);
+void modbus_set_holding_register(u16 addr, u16 value);
+
+enum modbus_id_object {
+ MODBUS_ID_VENDOR_NAME, // first three must be always defined
+ MODBUS_ID_PRODUCT_CODE,
+ MODBUS_ID_MAJOR_MINOR_REVISION,
+ MODBUS_ID_VENDOR_URL, // the rest may be NULL
+ MODBUS_ID_PRODUCT_NAME,
+ MODBUS_ID_USER_APP_NAME,
+ MODBUS_ID_MAX,
+};
+
+extern const char * const modbus_id_strings[MODBUS_ID_MAX];
+
+#endif
--- /dev/null
+#include "util.h"
+
+#include <libopencm3/stm32/usart.h>
+
+#include <stdarg.h>
+#include <string.h>
+
+/*** Configuration ***/
+
+// You should set the following parameters in config.h
+
+// Use the semi-hosting interface for debugging messages
+// #define DEBUG_SEMIHOSTING
+
+// Use this USART for debugging messages
+// #define DEBUG_USART USART1
+
+/*** Implementation ***/
+
+#ifdef DEBUG_SEMIHOSTING
+
+void semi_put_char(char c)
+{
+ // This is tricky, we need to work around GCC bugs
+ volatile char cc = c;
+ asm volatile (
+ "mov r0, #0x03\n" /* SYS_WRITEC */
+ "mov r1, %[msg]\n"
+ "bkpt #0xAB\n"
+ :
+ : [msg] "r" (&cc)
+ : "r0", "r1"
+ );
+}
+
+void semi_write_string(char *c)
+{
+ asm volatile (
+ "mov r0, #0x04\n" /* SYS_WRITE0 */
+ "mov r1, %[msg]\n"
+ "bkpt #0xAB\n"
+ :
+ : [msg] "r" (c)
+ : "r0", "r1"
+ );
+}
+
+#endif
+
+void debug_putc(int c)
+{
+#ifdef DEBUG_SEMIHOSTING
+ static char debug_buf[128];
+ static int debug_i;
+ debug_buf[debug_i++] = c;
+ if (c == '\n' || debug_i >= sizeof(debug_buf) - 1) {
+ debug_buf[debug_i] = 0;
+ semi_write_string(debug_buf);
+ debug_i = 0;
+ }
+#endif
+#ifdef DEBUG_USART
+ if (c == '\n')
+ usart_send_blocking(USART2, '\r');
+ usart_send_blocking(USART2, c);
+#endif
+}
+
+void debug_puts(const char *s)
+{
+ while (*s)
+ debug_putc(*s++);
+}
+
+enum printf_flags {
+ PF_ZERO_PAD = 1,
+ PF_SIGNED = 2,
+ PF_NEGATIVE = 4,
+ PF_UPPERCASE = 8,
+ PF_LEFT = 16,
+};
+
+static void printf_string(const char *s, uint width, uint flags)
+{
+ uint len = strlen(s);
+ uint pad = (len < width) ? width - len : 0;
+ char pad_char = (flags & PF_ZERO_PAD) ? '0' : ' ';
+
+ if (flags & PF_LEFT)
+ debug_puts(s);
+ while (pad--)
+ debug_putc(pad_char);
+ if (!(flags & PF_LEFT))
+ debug_puts(s);
+}
+
+static void printf_number(uint i, uint width, uint flags, uint base)
+{
+ char buf[16];
+ char *w = buf + sizeof(buf);
+
+ if (flags & PF_SIGNED) {
+ if ((int) i < 0) {
+ i = - (int) i;
+ flags |= PF_NEGATIVE;
+ }
+ }
+
+ *--w = 0;
+ do {
+ uint digit = i % base;
+ if (digit < 10)
+ *--w = '0' + digit;
+ else
+ *--w = ((flags & PF_UPPERCASE) ? 'A' : 'a') + digit - 10;
+ i /= base;
+ }
+ while (i);
+
+ if (flags & PF_NEGATIVE)
+ *--w = '-';
+
+ printf_string(w, width, flags);
+}
+
+void debug_printf(const char *fmt, ...)
+{
+ va_list args;
+ va_start(args, fmt);
+
+ while (*fmt) {
+ int c = *fmt++;
+ if (c != '%') {
+ debug_putc(c);
+ continue;
+ }
+
+ uint width = 0;
+ uint flags = 0;
+
+ if (*fmt == '-') {
+ fmt++;
+ flags |= PF_LEFT;
+ }
+
+ if (*fmt == '0') {
+ fmt++;
+ flags |= PF_ZERO_PAD;
+ }
+
+ while (*fmt >= '0' && *fmt <= '9')
+ width = 10*width + *fmt++ - '0';
+
+ c = *fmt++;
+ switch (c) {
+ case 'd':
+ printf_number(va_arg(args, int), width, flags | PF_SIGNED, 10);
+ break;
+ case 'u':
+ printf_number(va_arg(args, int), width, flags, 10);
+ break;
+ case 'X':
+ flags |= PF_UPPERCASE;
+ // fall-thru
+ case 'x':
+ printf_number(va_arg(args, int), width, flags, 16);
+ break;
+ case 's':
+ printf_string(va_arg(args, char *), width, flags);
+ break;
+ default:
+ debug_putc(c);
+ continue;
+ }
+ }
+
+ va_end(args);
+}
--- /dev/null
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "config.h"
+
+typedef unsigned int uint;
+typedef uint8_t byte;
+typedef uint16_t u16;
+typedef int16_t s16;
+typedef uint32_t u32;
+typedef int32_t s32;
+
+#define MIN(x,y) ((x) < (y) ? (x) : (y))
+#define MAX(x,y) ((x) > (y) ? (x) : (y))
+
+#define UNUSED __attribute__((unused))
+
+static inline uint get_u16_le(byte *p)
+{
+ return (p[1] << 8) | p[0];
+}
+
+static inline uint get_u16_be(byte *p)
+{
+ return (p[0] << 8) | p[1];
+}
+
+static inline uint get_u32_le(byte *p)
+{
+ return (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0];
+}
+
+static inline uint get_u32_be(byte *p)
+{
+ return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
+}
+
+static inline void put_u16_le(byte *p, u16 x)
+{
+ p[0] = x;
+ p[1] = x >> 8;
+}
+
+static inline void put_u16_be(byte *p, u16 x)
+{
+ p[0] = x >> 8;
+ p[1] = x;
+}
+
+static inline void put_u32_be(byte *p, u32 x)
+{
+ p[0] = x >> 24;
+ p[1] = (x >> 16) & 0xff;
+ p[2] = (x >> 8) & 0xff;
+ p[3] = x & 0xff;
+}
+
+static inline void put_u32_le(byte *p, u32 x)
+{
+ p[3] = x >> 24;
+ p[2] = (x >> 16) & 0xff;
+ p[1] = (x >> 8) & 0xff;
+ p[0] = x & 0xff;
+}
+
+// debug.c
+
+void debug_printf(const char *fmt, ...);
+void debug_puts(const char *s);
+void debug_putc(int c);
BINARY=test
OBJS=test.o util-debug.o modbus.o
+vpath %.c ../lib
+
OPENCM3_DIR=/home/mj/stm/libopencm3
DEVICE=stm32f103x8
TGT_CFLAGS += -Wall -Wextra -Wshadow -Wimplicit-function-declaration
TGT_CFLAGS += -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes
TGT_CFLAGS += -fno-common -ffunction-sections -fdata-sections
+TGT_CFLAGS += -I. -I../lib
TGT_CPPFLAGS += -MD
%.o: %.c
@printf " CC $(*).c\n"
- $(Q)$(CC) $(TGT_CFLAGS) $(CFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $*.o -c $*.c
+ $(Q)$(CC) $(TGT_CFLAGS) $(CFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<
.PHONY: clean
clean:
+++ /dev/null
-/*
- * Generic MODBUS Library for STM32
- *
- * (c) 2019 Martin Mareš <mj@ucw.cz>
- */
-
-#include "util.h"
-#include "modbus.h"
-
-#include <stddef.h>
-#include <string.h>
-
-#include <libopencm3/cm3/nvic.h>
-#include <libopencm3/stm32/gpio.h>
-#include <libopencm3/stm32/usart.h>
-#include <libopencm3/stm32/timer.h>
-
-/*** Configuration ***/
-
-// You should set the following parameters in config.h
-
-// USART (pins are expected to be configured by the caller)
-// #define MODBUS_USART USART2
-// #define MODBUS_NVIC_USART_IRQ NVIC_USART2_IRQ
-// #define MODBUS_USART_ISR usart2_isr
-
-// GPIO pin for transmitter enable (pins is expected to be configured by the caller)
-// #define MODBUS_TXEN_GPIO_PORT GPIOA
-// #define MODBUS_TXEN_GPIO_PIN GPIO1
-
-// Timer
-// #define MODBUS_TIMER TIM2
-// #define MODBUS_NVIC_TIMER_IRQ NVIC_TIM2_IRQ
-// #define MODBUS_TIMER_ISR tim2_isr
-
-// Slave address we are responding at
-// #define MODBUS_OUR_ADDRESS 42
-
-// Baud rate
-#ifndef MODBUS_BAUD_RATE
-#define MODBUS_BAUD_RATE 19200
-#endif
-
-// CPU clock frequency
-// #define CPU_CLOCK_MHZ 72
-
-// Receive buffer size (standard specifies 256 bytes, you can make it shorter if necessary)
-#ifndef MODBUS_RX_BUFSIZE
-#define MODBUS_RX_BUFSIZE 256
-#endif
-
-// Transmit buffer size (standard specifies 256 bytes, you can make it shorter if necessary)
-#ifndef MODBUS_TX_BUFSIZE
-#define MODBUS_TX_BUFSIZE 256
-#endif
-
-// Receive timeout in microseconds
-#ifndef MODBUS_RX_TIMEOUT
-#if MODBUS_BAUD_RATE <= 19200
-// For low baud rates, the standard specifies timeout of 1.5 character times
-// (1 character = start bit + 8 data bits + parity bit + stop bit = 11 bits)
-#define MODBUS_RX_TIMEOUT (1000000*11*3/2/MODBUS_BAUD_RATE)
-#else
-// For high rates, the timeout is fixed to 750 μs
-#define MODBUS_RX_TIMEOUT 750
-#endif
-#endif
-
-/*** State ***/
-
-enum mb_state {
- STATE_RX,
- STATE_RX_DONE,
- STATE_PROCESSING,
- STATE_TX,
- STATE_TX_LAST,
- STATE_TX_DONE,
-};
-
-static byte rx_buf[MODBUS_RX_BUFSIZE];
-static u16 rx_size;
-static byte rx_bad;
-static byte state; // STATE_xxx
-
-static byte *rx_frame;
-static byte *rx_frame_end;
-
-static byte tx_buf[MODBUS_TX_BUFSIZE];
-static u16 tx_size;
-static u16 tx_pos;
-
-static bool check_frame(void);
-static void process_frame(void);
-
-/*** Low-level layer ***/
-
-static void rx_init(void)
-{
- state = STATE_RX;
- rx_size = 0;
- rx_bad = 0;
- usart_set_mode(MODBUS_USART, USART_MODE_RX);
- usart_enable_rx_interrupt(MODBUS_USART);
-}
-
-static void rx_done(void)
-{
- state = STATE_RX_DONE;
- usart_disable_rx_interrupt(MODBUS_USART);
-}
-
-static void tx_init(void)
-{
- state = STATE_TX;
- tx_pos = 0;
- gpio_set(MODBUS_TXEN_GPIO_PORT, MODBUS_TXEN_GPIO_PIN);
- usart_set_mode(MODBUS_USART, USART_MODE_TX);
- usart_enable_tx_interrupt(MODBUS_USART);
-}
-
-static void tx_done(void)
-{
- state = STATE_TX_DONE;
- // usart_disable_tx_interrupt(MODBUS_USART); // Already done by irq handler
- gpio_clear(MODBUS_TXEN_GPIO_PORT, MODBUS_TXEN_GPIO_PIN);
-}
-
-void modbus_init(void)
-{
- timer_set_prescaler(MODBUS_TIMER, CPU_CLOCK_MHZ-1); // 1 tick = 1 μs
- timer_set_mode(MODBUS_TIMER, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_DOWN);
- timer_update_on_overflow(MODBUS_TIMER);
- timer_disable_preload(MODBUS_TIMER);
- timer_one_shot_mode(MODBUS_TIMER);
- timer_enable_irq(MODBUS_TIMER, TIM_DIER_UIE);
- nvic_enable_irq(MODBUS_NVIC_TIMER_IRQ);
-
- gpio_clear(MODBUS_TXEN_GPIO_PORT, MODBUS_TXEN_GPIO_PIN);
-
- usart_set_baudrate(MODBUS_USART, MODBUS_BAUD_RATE);
- usart_set_databits(MODBUS_USART, 9);
- usart_set_stopbits(MODBUS_USART, USART_STOPBITS_1);
- usart_set_parity(MODBUS_USART, USART_PARITY_EVEN);
- usart_set_flow_control(MODBUS_USART, USART_FLOWCONTROL_NONE);
-
- rx_init();
-
- nvic_enable_irq(MODBUS_NVIC_USART_IRQ);
- usart_enable(MODBUS_USART);
-}
-
-void MODBUS_USART_ISR(void)
-{
- u32 status = USART_SR(MODBUS_USART);
-
- if (status & USART_SR_RXNE) {
- uint ch = usart_recv(MODBUS_USART);
- if (state == STATE_RX) {
- if (status & (USART_SR_FE | USART_SR_ORE | USART_SR_NE)) {
- rx_bad = 1;
- } else if (rx_size < MODBUS_RX_BUFSIZE) {
- rx_buf[rx_size++] = ch;
- } else {
- // Frame too long
- rx_bad = 2;
- }
- timer_set_period(MODBUS_TIMER, MODBUS_RX_TIMEOUT);
- timer_generate_event(MODBUS_TIMER, TIM_EGR_UG);
- timer_enable_counter(MODBUS_TIMER);
- }
- }
-
- if (state == STATE_TX) {
- if (status & USART_SR_TXE) {
- if (tx_pos < tx_size) {
- usart_send(MODBUS_USART, tx_buf[tx_pos++]);
- } else {
- // The transmitter is double-buffered, so at this moment, it is transmitting
- // the last byte of the frame. Wait until transfer is completed.
- usart_disable_tx_interrupt(MODBUS_USART);
- USART_CR1(MODBUS_USART) |= USART_CR1_TCIE;
- state = STATE_TX_LAST;
- }
- }
- } else if (state == STATE_TX_LAST) {
- if (status & USART_SR_TC) {
- // Transfer of the last byte is complete. Release the bus.
- USART_CR1(MODBUS_USART) &= ~USART_CR1_TCIE;
- tx_done();
- rx_init();
- }
- }
-}
-
-void MODBUS_TIMER_ISR(void)
-{
- if (TIM_SR(MODBUS_TIMER) & TIM_SR_UIF) {
- TIM_SR(MODBUS_TIMER) &= ~TIM_SR_UIF;
- if (state == STATE_RX)
- rx_done();
- }
-}
-
-void modbus_loop(void)
-{
- if (state != STATE_RX_DONE)
- return;
- state = STATE_PROCESSING;
-
- if (!check_frame()) {
- rx_init();
- return;
- }
-
- if (rx_buf[0] == MODBUS_OUR_ADDRESS) {
- // Frame addressed to us: process and reply
- process_frame();
- tx_init();
- } else if (rx_buf[0] == 0x00) {
- // Broadcast frame: process, but do not reply
- process_frame();
- rx_init();
- } else {
- // Somebody else's frame: discard
- rx_init();
- }
-}
-
-/** CRC ***/
-
-static const byte crc_hi[] = {
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
- 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
- 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40,
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
- 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41,
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
- 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40,
- 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
- 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40,
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40,
- 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
- 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40,
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
- 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
- 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40,
- 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0, 0x80, 0x41, 0x00, 0xc1,
- 0x81, 0x40, 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
- 0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41, 0x01, 0xc0,
- 0x80, 0x41, 0x00, 0xc1, 0x81, 0x40
-};
-
-static const byte crc_lo[] = {
- 0x00, 0xc0, 0xc1, 0x01, 0xc3, 0x03, 0x02, 0xc2, 0xc6, 0x06,
- 0x07, 0xc7, 0x05, 0xc5, 0xc4, 0x04, 0xcc, 0x0c, 0x0d, 0xcd,
- 0x0f, 0xcf, 0xce, 0x0e, 0x0a, 0xca, 0xcb, 0x0b, 0xc9, 0x09,
- 0x08, 0xc8, 0xd8, 0x18, 0x19, 0xd9, 0x1b, 0xdb, 0xda, 0x1a,
- 0x1e, 0xde, 0xdf, 0x1f, 0xdd, 0x1d, 0x1c, 0xdc, 0x14, 0xd4,
- 0xd5, 0x15, 0xd7, 0x17, 0x16, 0xd6, 0xd2, 0x12, 0x13, 0xd3,
- 0x11, 0xd1, 0xd0, 0x10, 0xf0, 0x30, 0x31, 0xf1, 0x33, 0xf3,
- 0xf2, 0x32, 0x36, 0xf6, 0xf7, 0x37, 0xf5, 0x35, 0x34, 0xf4,
- 0x3c, 0xfc, 0xfd, 0x3d, 0xff, 0x3f, 0x3e, 0xfe, 0xfa, 0x3a,
- 0x3b, 0xfb, 0x39, 0xf9, 0xf8, 0x38, 0x28, 0xe8, 0xe9, 0x29,
- 0xeb, 0x2b, 0x2a, 0xea, 0xee, 0x2e, 0x2f, 0xef, 0x2d, 0xed,
- 0xec, 0x2c, 0xe4, 0x24, 0x25, 0xe5, 0x27, 0xe7, 0xe6, 0x26,
- 0x22, 0xe2, 0xe3, 0x23, 0xe1, 0x21, 0x20, 0xe0, 0xa0, 0x60,
- 0x61, 0xa1, 0x63, 0xa3, 0xa2, 0x62, 0x66, 0xa6, 0xa7, 0x67,
- 0xa5, 0x65, 0x64, 0xa4, 0x6c, 0xac, 0xad, 0x6d, 0xaf, 0x6f,
- 0x6e, 0xae, 0xaa, 0x6a, 0x6b, 0xab, 0x69, 0xa9, 0xa8, 0x68,
- 0x78, 0xb8, 0xb9, 0x79, 0xbb, 0x7b, 0x7a, 0xba, 0xbe, 0x7e,
- 0x7f, 0xbf, 0x7d, 0xbd, 0xbc, 0x7c, 0xb4, 0x74, 0x75, 0xb5,
- 0x77, 0xb7, 0xb6, 0x76, 0x72, 0xb2, 0xb3, 0x73, 0xb1, 0x71,
- 0x70, 0xb0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
- 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9c, 0x5c,
- 0x5d, 0x9d, 0x5f, 0x9f, 0x9e, 0x5e, 0x5a, 0x9a, 0x9b, 0x5b,
- 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4b, 0x8b,
- 0x8a, 0x4a, 0x4e, 0x8e, 0x8f, 0x4f, 0x8d, 0x4d, 0x4c, 0x8c,
- 0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
- 0x43, 0x83, 0x41, 0x81, 0x80, 0x40
-};
-
-static u16 crc16(byte *buf, u16 len)
-{
- byte hi = 0xff, lo = 0xff;
-
- while (len--) {
- byte i = hi ^ *buf++;
- hi = lo ^ crc_hi[i];
- lo = crc_lo[i];
- }
-
- return (hi << 8 | lo);
-}
-
-/*** High-level layer ***/
-
-static bool check_frame(void)
-{
- if (rx_bad) {
- // FIXME: Error counters?
- return false;
- }
-
- if (rx_size < 4) {
- // FIXME: Error counters?
- return false;
- }
-
- u16 crc = crc16(rx_buf, rx_size - 2);
- u16 rx_crc = (rx_buf[rx_size-2] << 8) | rx_buf[rx_size-1];
- if (crc != rx_crc) {
- // FIXME: Error counters?
- return false;
- }
-
- rx_frame = rx_buf + 1;
- rx_frame_end = rx_frame + rx_size - 2;
- return true;
-}
-
-enum mb_function {
- FUNC_READ_COILS = 0x01,
- FUNC_READ_DISCRETE_INPUTS = 0x02,
- FUNC_READ_HOLDING_REGISTERS = 0x03,
- FUNC_READ_INPUT_REGISTERS = 0x04,
- FUNC_WRITE_SINGLE_COIL = 0x05,
- FUNC_WRITE_SINGLE_REGISTER = 0x06,
- FUNC_READ_EXCEPTION_STATUS = 0x07,
- FUNC_DIAGNOSTICS = 0x08,
- FUNC_GET_COMM_EVENT_COUNTER = 0x0b,
- FUNC_GET_COMM_EVENT_LOG = 0x0c,
- FUNC_WRITE_MULTIPLE_COILS = 0x0f,
- FUNC_WRITE_MULTIPLE_REGISTERS = 0x10,
- FUNC_REPORT_SLAVE_ID = 0x11,
- FUNC_READ_FILE_RECORD = 0x14,
- FUNC_WRITE_FILE_RECORD = 0x15,
- FUNC_MASK_WRITE_REGISTER = 0x16,
- FUNC_READ_WRITE_MULTIPLE_REGISTERS = 0x17,
- FUNC_READ_FIFO_QUEUE = 0x18,
- FUNC_ENCAPSULATED_INTERFACE_TRANSPORT = 0x2b,
-};
-
-enum mb_error {
- ERR_ILLEGAL_FUNCTION = 0x01,
- ERR_ILLEGAL_DATA_ADDRESS = 0x02,
- ERR_ILLEGAL_DATA_VALUE = 0x03,
-};
-
-static uint read_remains(void)
-{
- return rx_frame_end - rx_frame;
-}
-
-static byte read_byte(void)
-{
- return *rx_frame++;
-}
-
-static u16 read_u16(void)
-{
- byte hi = *rx_frame++;
- byte lo = *rx_frame++;
- return (hi << 8) | lo;
-}
-
-static void write_byte(byte v)
-{
- tx_buf[tx_size++] = v;
-}
-
-static void write_u16(u16 v)
-{
- write_byte(v >> 8);
- write_byte(v);
-}
-
-static bool body_fits(uint body_len)
-{
- // body_len excludes slave address, function code, and CRC
- return (2 + body_len + 2 <= MODBUS_TX_BUFSIZE);
-}
-
-static void report_error(byte code)
-{
- // Discard the partially constructed body of the reply and rewrite the header
- tx_buf[1] |= 0x80;
- tx_buf[2] = code;
- tx_size = 3;
-}
-
-static void func_read_bits(bool coils)
-{
- if (read_remains() < 4)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 start = read_u16();
- u16 count = read_u16();
-
- uint bytes = (count+7) / 8;
- if (!body_fits(1 + bytes))
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- for (u16 i = 0; i < count; i++)
- if (!(coils ? modbus_check_coil : modbus_check_discrete_input)(start + i))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- write_byte(bytes);
- for (u16 i = 0; i < bytes; i++) {
- byte b = 0;
- for (byte j = 0; j < 8 && 8*i + j < count; j++) {
- uint addr = start + 8*i + j;
- if ((coils ? modbus_get_coil : modbus_get_discrete_input)(addr))
- b |= 1 << j;
- }
- write_byte(b);
- }
-}
-
-static void func_read_registers(byte holding)
-{
- if (read_remains() < 4)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 start = read_u16();
- u16 count = read_u16();
-
- uint bytes = 2*count;
- if (!body_fits(1 + bytes))
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- for (u16 i = 0; i < count; i++)
- if (!(holding ? modbus_check_holding_register : modbus_check_input_register)(start + i))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- // FIXME: Reporting of slave failures?
- write_byte(bytes);
- for (u16 i = 0; i < count; i++)
- write_u16((holding ? modbus_get_holding_register : modbus_get_input_register)(start + i));
-}
-
-static void func_write_single_coil(void)
-{
- if (read_remains() < 4)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 addr = read_u16();
- u16 value = read_u16();
-
- if (!modbus_check_coil(addr))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
- if (value != 0x0000 && value != 0xff00)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- modbus_set_coil(addr, value);
-}
-
-static void func_write_single_register(void)
-{
- if (read_remains() < 4)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 addr = read_u16();
- u16 value = read_u16();
-
- if (!modbus_check_holding_register(addr))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- modbus_set_holding_register(addr, value);
-}
-
-static void func_write_multiple_coils(void)
-{
- if (read_remains() < 5)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 start = read_u16();
- u16 count = read_u16();
- byte bytes = read_byte();
-
- if (read_remains() < bytes || bytes != (count+7) / 8)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- for (u16 i = 0; i < count; i++)
- if (!modbus_check_coil(start + i))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- for (u16 i = 0; i < count; i++)
- modbus_set_coil(start + i, rx_frame[i/8] & (1U << (i%8)));
-}
-
-static void func_write_multiple_registers(void)
-{
- if (read_remains() < 5)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 start = read_u16();
- u16 count = read_u16();
- byte bytes = read_byte();
-
- if (read_remains() < bytes || bytes != 2*count)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- for (u16 i = 0; i < count; i++)
- if (!modbus_check_holding_register(start + i))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- for (u16 i = 0; i < count; i++)
- modbus_set_holding_register(start + i, read_u16());
-}
-
-static void func_mask_write_register(void)
-{
- if (read_remains() < 6)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 addr = read_u16();
- u16 and_mask = read_u16();
- u16 or_mask = read_u16();
-
- if (!modbus_check_holding_register(addr))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- u16 reg = modbus_get_holding_register(addr);
- reg = (reg & and_mask) | (or_mask & ~and_mask);
- modbus_set_holding_register(addr, reg);
-}
-
-static void func_read_write_multiple_registers(void)
-{
- if (read_remains() < 9)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- u16 read_start = read_u16();
- u16 read_count = read_u16();
- u16 write_start = read_u16();
- u16 write_count = read_u16();
- byte write_bytes = read_byte();
-
- if (read_remains() < write_bytes || write_bytes != 2*write_count)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- for (u16 i = 0; i < read_count; i++)
- if (!modbus_check_holding_register(read_start + i))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- for (u16 i = 0; i < write_count; i++)
- if (!modbus_check_holding_register(write_start + i))
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
-
- byte read_bytes = 2*write_count;
- if (!body_fits(1 + read_bytes))
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- for (u16 i = 0; i < write_count; i++)
- modbus_set_holding_register(write_start + i, read_u16());
-
- write_byte(read_bytes);
- for (u16 i = 0; i < read_count; i++)
- modbus_get_holding_register(read_start + i);
-}
-
-static void func_encapsulated_interface_transport(void)
-{
- if (read_remains() < 3 ||
- read_byte() != 0x0e)
- return report_error(ERR_ILLEGAL_DATA_VALUE);
-
- byte action = read_byte();
- byte id = read_byte();
-
- byte range_min, range_max;
- switch (action) {
- case 1:
- // Streaming access to basic identification
- range_min = MODBUS_ID_VENDOR_NAME;
- range_max = MODBUS_ID_MAJOR_MINOR_REVISION;
- break;
- case 2:
- // Streaming access to regular identification
- range_min = MODBUS_ID_VENDOR_URL;
- range_max = MODBUS_ID_USER_APP_NAME;
- break;
- case 4:
- // Individual access
- if (id >= MODBUS_ID_MAX || !modbus_id_strings[id])
- return report_error(ERR_ILLEGAL_DATA_ADDRESS);
- range_min = range_max = id;
- break;
- default:
- return report_error(ERR_ILLEGAL_DATA_VALUE);
- }
-
- if (action != 4) {
- if (id < range_min || id > range_max)
- id = range_min;
- }
-
- write_byte(0x0e); // Repeat a part of the request
- write_byte(action);
-
- // Conformity level
- if (modbus_id_strings[MODBUS_ID_VENDOR_URL] ||
- modbus_id_strings[MODBUS_ID_PRODUCT_NAME] ||
- modbus_id_strings[MODBUS_ID_USER_APP_NAME])
- write_byte(0x82); // Regular identification, both stream and individual access supported
- else
- write_byte(0x81); // Basic identification only
-
- u16 more_follows_at = tx_size;
- write_byte(0); // More follows: so far not
- write_byte(0); // Next object ID: so far none
- write_byte(0); // Number of objects
-
- for (id = range_min; id <= range_max; id++) {
- if (modbus_id_strings[id]) {
- byte len = strlen(modbus_id_strings[id]);
- byte remains = MODBUS_TX_BUFSIZE - 4 - tx_size; // 2 for CRC, 2 for object header
- if (len > remains) {
- // If it is the only object, cut it
- if (!tx_buf[more_follows_at + 2])
- len = remains;
- else {
- // More follows, report the next ID
- tx_buf[more_follows_at] = 0xff;
- tx_buf[more_follows_at + 1] = id;
- break;
- }
- }
- tx_buf[more_follows_at + 2] ++;
- write_byte(id);
- write_byte(len);
- memcpy(tx_buf + tx_size, modbus_id_strings[id], len);
- tx_size += len;
- }
- }
-}
-
-static void process_frame(void)
-{
- byte func = read_byte();
-
- // Prepare reply frame
- tx_buf[0] = MODBUS_OUR_ADDRESS;
- tx_buf[1] = rx_buf[1];
- tx_size = 2;
-
- switch (func) {
- case FUNC_READ_COILS:
- func_read_bits(true);
- break;
- case FUNC_READ_DISCRETE_INPUTS:
- func_read_bits(false);
- break;
- case FUNC_READ_HOLDING_REGISTERS:
- func_read_registers(true);
- break;
- case FUNC_READ_INPUT_REGISTERS:
- func_read_registers(false);
- break;
- case FUNC_WRITE_SINGLE_COIL:
- func_write_single_coil();
- break;
- case FUNC_WRITE_SINGLE_REGISTER:
- func_write_single_register();
- break;
- case FUNC_WRITE_MULTIPLE_COILS:
- func_write_multiple_coils();
- break;
- case FUNC_WRITE_MULTIPLE_REGISTERS:
- func_write_multiple_registers();
- break;
- case FUNC_MASK_WRITE_REGISTER:
- func_mask_write_register();
- break;
- case FUNC_READ_WRITE_MULTIPLE_REGISTERS:
- func_read_write_multiple_registers();
- break;
- case FUNC_ENCAPSULATED_INTERFACE_TRANSPORT:
- func_encapsulated_interface_transport();
- break;
- default:
- report_error(ERR_ILLEGAL_FUNCTION);
- }
-
- // Finish reply frame
- write_u16(crc16(tx_buf, tx_size));
-}
+++ /dev/null
-/*
- * Generic MODBUS Library for STM32
- *
- * (c) 2019 Martin Mareš <mj@ucw.cz>
- */
-
-#ifndef _MODBUS_H
-#define _MODBUS_H
-
-void modbus_init(void);
-void modbus_loop(void);
-
-// Callbacks
-
-bool modbus_check_discrete_input(u16 addr);
-bool modbus_get_discrete_input(u16 addr);
-
-bool modbus_check_coil(u16 addr);
-bool modbus_get_coil(u16 addr);
-void modbus_set_coil(u16 addr, bool value);
-
-bool modbus_check_input_register(u16 addr);
-u16 modbus_get_input_register(u16 addr);
-
-bool modbus_check_holding_register(u16 addr);
-u16 modbus_get_holding_register(u16 addr);
-void modbus_set_holding_register(u16 addr, u16 value);
-
-enum modbus_id_object {
- MODBUS_ID_VENDOR_NAME, // first three must be always defined
- MODBUS_ID_PRODUCT_CODE,
- MODBUS_ID_MAJOR_MINOR_REVISION,
- MODBUS_ID_VENDOR_URL, // the rest may be NULL
- MODBUS_ID_PRODUCT_NAME,
- MODBUS_ID_USER_APP_NAME,
- MODBUS_ID_MAX,
-};
-
-extern const char * const modbus_id_strings[MODBUS_ID_MAX];
-
-#endif
+++ /dev/null
-#include "util.h"
-
-#include <libopencm3/stm32/usart.h>
-
-#include <stdarg.h>
-#include <string.h>
-
-/*** Configuration ***/
-
-// You should set the following parameters in config.h
-
-// Use the semi-hosting interface for debugging messages
-// #define DEBUG_SEMIHOSTING
-
-// Use this USART for debugging messages
-// #define DEBUG_USART USART1
-
-/*** Implementation ***/
-
-#ifdef DEBUG_SEMIHOSTING
-
-void semi_put_char(char c)
-{
- // This is tricky, we need to work around GCC bugs
- volatile char cc = c;
- asm volatile (
- "mov r0, #0x03\n" /* SYS_WRITEC */
- "mov r1, %[msg]\n"
- "bkpt #0xAB\n"
- :
- : [msg] "r" (&cc)
- : "r0", "r1"
- );
-}
-
-void semi_write_string(char *c)
-{
- asm volatile (
- "mov r0, #0x04\n" /* SYS_WRITE0 */
- "mov r1, %[msg]\n"
- "bkpt #0xAB\n"
- :
- : [msg] "r" (c)
- : "r0", "r1"
- );
-}
-
-#endif
-
-void debug_putc(int c)
-{
-#ifdef DEBUG_SEMIHOSTING
- static char debug_buf[128];
- static int debug_i;
- debug_buf[debug_i++] = c;
- if (c == '\n' || debug_i >= sizeof(debug_buf) - 1) {
- debug_buf[debug_i] = 0;
- semi_write_string(debug_buf);
- debug_i = 0;
- }
-#endif
-#ifdef DEBUG_USART
- if (c == '\n')
- usart_send_blocking(USART2, '\r');
- usart_send_blocking(USART2, c);
-#endif
-}
-
-void debug_puts(const char *s)
-{
- while (*s)
- debug_putc(*s++);
-}
-
-enum printf_flags {
- PF_ZERO_PAD = 1,
- PF_SIGNED = 2,
- PF_NEGATIVE = 4,
- PF_UPPERCASE = 8,
- PF_LEFT = 16,
-};
-
-static void printf_string(const char *s, uint width, uint flags)
-{
- uint len = strlen(s);
- uint pad = (len < width) ? width - len : 0;
- char pad_char = (flags & PF_ZERO_PAD) ? '0' : ' ';
-
- if (flags & PF_LEFT)
- debug_puts(s);
- while (pad--)
- debug_putc(pad_char);
- if (!(flags & PF_LEFT))
- debug_puts(s);
-}
-
-static void printf_number(uint i, uint width, uint flags, uint base)
-{
- char buf[16];
- char *w = buf + sizeof(buf);
-
- if (flags & PF_SIGNED) {
- if ((int) i < 0) {
- i = - (int) i;
- flags |= PF_NEGATIVE;
- }
- }
-
- *--w = 0;
- do {
- uint digit = i % base;
- if (digit < 10)
- *--w = '0' + digit;
- else
- *--w = ((flags & PF_UPPERCASE) ? 'A' : 'a') + digit - 10;
- i /= base;
- }
- while (i);
-
- if (flags & PF_NEGATIVE)
- *--w = '-';
-
- printf_string(w, width, flags);
-}
-
-void debug_printf(const char *fmt, ...)
-{
- va_list args;
- va_start(args, fmt);
-
- while (*fmt) {
- int c = *fmt++;
- if (c != '%') {
- debug_putc(c);
- continue;
- }
-
- uint width = 0;
- uint flags = 0;
-
- if (*fmt == '-') {
- fmt++;
- flags |= PF_LEFT;
- }
-
- if (*fmt == '0') {
- fmt++;
- flags |= PF_ZERO_PAD;
- }
-
- while (*fmt >= '0' && *fmt <= '9')
- width = 10*width + *fmt++ - '0';
-
- c = *fmt++;
- switch (c) {
- case 'd':
- printf_number(va_arg(args, int), width, flags | PF_SIGNED, 10);
- break;
- case 'u':
- printf_number(va_arg(args, int), width, flags, 10);
- break;
- case 'X':
- flags |= PF_UPPERCASE;
- // fall-thru
- case 'x':
- printf_number(va_arg(args, int), width, flags, 16);
- break;
- case 's':
- printf_string(va_arg(args, char *), width, flags);
- break;
- default:
- debug_putc(c);
- continue;
- }
- }
-
- va_end(args);
-}
+++ /dev/null
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdint.h>
-
-#include "config.h"
-
-typedef unsigned int uint;
-typedef uint8_t byte;
-typedef uint16_t u16;
-typedef int16_t s16;
-typedef uint32_t u32;
-typedef int32_t s32;
-
-#define MIN(x,y) ((x) < (y) ? (x) : (y))
-#define MAX(x,y) ((x) > (y) ? (x) : (y))
-
-#define UNUSED __attribute__((unused))
-
-static inline uint get_u16_le(byte *p)
-{
- return (p[1] << 8) | p[0];
-}
-
-static inline uint get_u16_be(byte *p)
-{
- return (p[0] << 8) | p[1];
-}
-
-static inline uint get_u32_le(byte *p)
-{
- return (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0];
-}
-
-static inline uint get_u32_be(byte *p)
-{
- return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
-}
-
-static inline void put_u16_le(byte *p, u16 x)
-{
- p[0] = x;
- p[1] = x >> 8;
-}
-
-static inline void put_u16_be(byte *p, u16 x)
-{
- p[0] = x >> 8;
- p[1] = x;
-}
-
-static inline void put_u32_be(byte *p, u32 x)
-{
- p[0] = x >> 24;
- p[1] = (x >> 16) & 0xff;
- p[2] = (x >> 8) & 0xff;
- p[3] = x & 0xff;
-}
-
-static inline void put_u32_le(byte *p, u32 x)
-{
- p[3] = x >> 24;
- p[2] = (x >> 16) & 0xff;
- p[1] = (x >> 8) & 0xff;
- p[0] = x & 0xff;
-}
-
-// debug.c
-
-void debug_printf(const char *fmt, ...);
-void debug_puts(const char *s);
-void debug_putc(int c);
projects / home-hw.git / commitdiff