X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=test-modbus%2Fmodbus.c;h=c6336460d307d1a8fe814e77b3159409ddaeb113;hb=85467d44920f4e69cc14d793fc1440520b80ac84;hp=da788a29fd85a3af7eb3c3c12316457ce65ae84e;hpb=f8c650828fe1cedb50bc66b636ab76756ec67837;p=home-hw.git diff --git a/test-modbus/modbus.c b/test-modbus/modbus.c index da788a2..c633646 100644 --- a/test-modbus/modbus.c +++ b/test-modbus/modbus.c @@ -1,11 +1,73 @@ +/* + * Generic MODBUS Library for STM32 + * + * (c) 2019 Martin Mareš + */ + #include "util.h" #include "modbus.h" +#include +#include + #include #include #include #include +/*** 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, @@ -15,216 +77,213 @@ enum mb_state { STATE_TX_DONE, }; -#define RX_BUFSIZE 256 -#define TX_BUFSIZE 256 - -static byte rx_buf[RX_BUFSIZE]; +static byte rx_buf[MODBUS_RX_BUFSIZE]; static u16 rx_size; static byte rx_bad; static byte state; // STATE_xxx -static byte tx_buf[TX_BUFSIZE]; +static byte *rx_frame; +static byte *rx_frame_end; + +static byte tx_buf[MODBUS_TX_BUFSIZE]; static u16 tx_size; static u16 tx_pos; -#define MB_OUR_ADDRESS 42 +static bool check_frame(void); +static void process_frame(void); -static void UNUSED xx_write_char(uint c) // FIXME -{ - usart_set_mode(USART2, USART_MODE_TX); - gpio_set(GPIOA, GPIO1); - usart_send_blocking(USART2, c); - while (!usart_get_flag(USART2, USART_SR_TC)) - ; - gpio_clear(GPIOA, GPIO1); - usart_set_mode(USART2, USART_MODE_RX); -} +/*** Low-level layer ***/ static void rx_init(void) { state = STATE_RX; rx_size = 0; rx_bad = 0; - usart_set_mode(USART2, USART_MODE_RX); - usart_enable_rx_interrupt(USART2); + 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(USART2); + usart_disable_rx_interrupt(MODBUS_USART); } static void tx_init(void) { state = STATE_TX; tx_pos = 0; - gpio_set(GPIOA, GPIO1); - usart_set_mode(USART2, USART_MODE_TX); - usart_enable_tx_interrupt(USART2); + 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(USART2); // Already done by irq handler - gpio_clear(GPIOA, GPIO1); + // 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(TIM2, 71); // 1 tick = 1 μs - timer_set_mode(TIM2, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_DOWN); - timer_update_on_overflow(TIM2); - timer_disable_preload(TIM2); - timer_one_shot_mode(TIM2); - timer_enable_irq(TIM2, TIM_DIER_UIE); - nvic_enable_irq(NVIC_TIM2_IRQ); - - gpio_set_mode(GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO_USART2_RX); - gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX); - - gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO1); - gpio_clear(GPIOA, GPIO1); - - usart_set_baudrate(USART2, 19200); - usart_set_databits(USART2, 8); - usart_set_stopbits(USART2, USART_STOPBITS_1); - usart_set_parity(USART2, USART_PARITY_NONE); - // usart_set_parity(USART2, USART_PARITY_EVEN); // FIXME - usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE); + 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(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 + nvic_enable_irq(MODBUS_NVIC_USART_IRQ); + usart_enable(MODBUS_USART); } -void usart2_isr(void) +void MODBUS_USART_ISR(void) { - u32 status = USART_SR(USART2); - - // FIXME: Optimize + u32 status = USART_SR(MODBUS_USART); if (status & USART_SR_RXNE) { - uint ch = usart_recv(USART2); + uint ch = usart_recv(MODBUS_USART); if (state == STATE_RX) { -#if 0 if (status & (USART_SR_FE | USART_SR_ORE | USART_SR_NE)) { rx_bad = 1; - } else -#endif - if (rx_size < RX_BUFSIZE) { + } else if (rx_size < MODBUS_RX_BUFSIZE) { rx_buf[rx_size++] = ch; } else { // Frame too long rx_bad = 2; } - timer_set_period(TIM2, 7500); // 0.75 ms timeout for end of frame (FIXME: right value?) - timer_generate_event(TIM2, TIM_EGR_UG); - timer_enable_counter(TIM2); + 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(USART2, tx_buf[tx_pos++]); + 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(USART2); - USART_CR1(USART2) |= USART_CR1_TCIE; + usart_disable_tx_interrupt(MODBUS_USART); + USART_CR1(MODBUS_USART) |= USART_CR1_TCIE; state = STATE_TX_LAST; } } - } - - if (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(USART2) &= ~USART_CR1_TCIE; + USART_CR1(MODBUS_USART) &= ~USART_CR1_TCIE; tx_done(); rx_init(); } } } -void tim2_isr(void) +void MODBUS_TIMER_ISR(void) { - if (TIM_SR(TIM2) & TIM_SR_UIF) { - TIM_SR(TIM2) &= ~TIM_SR_UIF; + if (TIM_SR(MODBUS_TIMER) & TIM_SR_UIF) { + TIM_SR(MODBUS_TIMER) &= ~TIM_SR_UIF; if (state == STATE_RX) rx_done(); } } -// CRC tables +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 + 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 + 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) @@ -240,6 +299,8 @@ static u16 crc16(byte *buf, u16 len) return (hi << 8 | lo); } +/*** High-level layer ***/ + static bool check_frame(void) { if (rx_bad) { @@ -259,11 +320,31 @@ static bool check_frame(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 { @@ -272,6 +353,40 @@ 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 <= MODBUS_TX_BUFSIZE); +} + static void report_error(byte code) { // Discard the partially constructed body of the reply and rewrite the header @@ -280,55 +395,300 @@ static void report_error(byte 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 = rx_buf[1]; + byte func = read_byte(); // Prepare reply frame - tx_buf[0] = MB_OUR_ADDRESS; + 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: - 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; -} - -void modbus_loop(void) -{ - if (state != STATE_RX_DONE) { - // gpio_toggle(GPIOC, GPIO13); - return; - } - state = STATE_PROCESSING; - gpio_toggle(GPIOC, GPIO13); - - if (!check_frame()) { - rx_init(); - return; - } - - if (rx_buf[0] == MB_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(); - } + write_u16(crc16(tx_buf, tx_size)); }