#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>
static byte rx_bad;
static byte state; // STATE_xxx
+static byte *rx_frame;
+static byte *rx_frame_end;
+
static byte tx_buf[TX_BUFSIZE];
static u16 tx_size;
static u16 tx_pos;
gpio_clear(GPIOA, GPIO1);
usart_set_baudrate(USART2, 19200);
- usart_set_databits(USART2, 8);
+ usart_set_databits(USART2, 9);
usart_set_stopbits(USART2, USART_STOPBITS_1);
- usart_set_parity(USART2, USART_PARITY_NONE);
- // usart_set_parity(USART2, USART_PARITY_EVEN); // FIXME
+ // usart_set_parity(USART2, USART_PARITY_NONE);
+ usart_set_parity(USART2, USART_PARITY_EVEN);
usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE);
rx_init();
nvic_enable_irq(NVIC_USART2_IRQ);
usart_enable(USART2);
-
-#if 0
- u32 xxx = USART_CR1(USART2);
- usart_set_mode(USART2, USART_MODE_TX);
- gpio_set(GPIOA, GPIO1);
- debug_printf("%08x\n", xxx);
- xx_write_char('\n');
-#endif
}
void usart2_isr(void)
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_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 <= TX_BUFSIZE);
+}
+
static void report_error(byte code)
{
// Discard the partially constructed body of the reply and rewrite the header
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 = 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 = rx_buf[1];
+ byte func = read_byte();
// Prepare reply frame
tx_buf[0] = MB_OUR_ADDRESS;
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:
- tx_buf[tx_size++] = 2;
- tx_buf[tx_size++] = 0x12;
- tx_buf[tx_size++] = 0x34;
+ 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
- u16 crc = crc16(tx_buf, tx_size);
- tx_buf[tx_size++] = crc >> 8;
- tx_buf[tx_size++] = crc;
+ write_u16(crc16(tx_buf, tx_size));
}
void modbus_loop(void)
{
- if (state != STATE_RX_DONE) {
- // gpio_toggle(GPIOC, GPIO13);
+ if (state != STATE_RX_DONE)
return;
- }
state = STATE_PROCESSING;
- gpio_toggle(GPIOC, GPIO13);
if (!check_frame()) {
rx_init();
rx_init();
}
}
+
+/*** Callbacks ***/
+
+bool modbus_check_discrete_input(u16 addr UNUSED)
+{
+ return false;
+}
+
+bool modbus_get_discrete_input(u16 addr UNUSED)
+{
+ return false;
+}
+
+bool modbus_check_coil(u16 addr UNUSED)
+{
+ return false;
+}
+
+bool modbus_get_coil(u16 addr UNUSED)
+{
+ return false;
+}
+
+void modbus_set_coil(u16 addr UNUSED, bool value UNUSED)
+{
+}
+
+bool modbus_check_input_register(u16 addr UNUSED)
+{
+ return false;
+}
+
+u16 modbus_get_input_register(u16 addr UNUSED)
+{
+ return 0;
+}
+
+bool modbus_check_holding_register(u16 addr UNUSED)
+{
+ return (addr == 0);
+}
+
+u16 modbus_get_holding_register(u16 addr UNUSED)
+{
+ return 0xbeef;
+}
+
+void modbus_set_holding_register(u16 addr UNUSED, u16 value UNUSED)
+{
+}
+
+const char * const modbus_id_strings[MODBUS_ID_MAX] = {
+ [MODBUS_ID_VENDOR_NAME] = "United Computer Wizards",
+ [MODBUS_ID_PRODUCT_CODE] = "42",
+ [MODBUS_ID_MAJOR_MINOR_REVISION] = "1.0",
+ [MODBUS_ID_VENDOR_URL] = "http://www.ucw.cz/",
+ [MODBUS_ID_PRODUCT_NAME] = "Magic Gadget",
+ [MODBUS_ID_USER_APP_NAME] = NULL,
+};
projects / home-hw.git / blobdiff