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Modbus refactor

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This commit is contained in:
mj 2021-12-05 16:36:41 +01:00
parent 13e1ba0ab1
commit 6dbbccec33
3 changed files with 267 additions and 119 deletions
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46
fw/Core/Inc/modbus.h
View File

@ -39,6 +39,7 @@
#define SRC_MODBUS_H_
#include "stdint.h"
#include "stddef.h"
/*
* Defines & macros
@ -48,10 +49,13 @@
#define MODBUS_DEFAULT_SLAVE_ADDRESS 254 /* 255 may be used for bridge device */
/* minimal frame length is 4 bytes: 1 B slave address, 1 B function code, 2 B CRC */
#define MODBUS_MINIMAL_FRAME_LEN 4
#define MODBUS_READ_DEVICE_ID_REQUEST_LEN 4
#define MODBUS_MAX_RTU_FRAME_SIZE 256
#define MODBUS_BUFFER_SIZE MODBUS_MAX_RTU_FRAME_SIZE /* alias */
#define MODBUS_ERROR_FLAG 0x80
#define MODBUS_MAX_REGISTERS 125
#define MODBUS_MEI 0x0E
#define MODBUS_DEVICE_ID_INDIVIDUAL_ACCESS_FLAG 0x80
/*
* Return values
@ -64,6 +68,7 @@
#define MODBUS_ERROR_OUT_OF_BOUNDS -4 // requested register is out of bounds
#define MODBUS_ERROR_FUNCTION_NOT_IMPLEMENTED -5 // function not implemented in callback
#define MODBUS_ERROR_REGISTER_NOT_IMPLEMENTED -6 // register not implemented in callback
#define MODBUS_ERROR_DEVICE_ID_NOT_IMPLEMENTED -7
/*
* Data types
@ -115,19 +120,18 @@ typedef enum {
MODBUS_EXCEPTION_MEMORY_PARITY_ERROR = 8,
MODBUS_EXCEPTION_GATEWAY_PATH_UNAVAILABLE = 10,
MODBUS_EXCEPTION_GATEWAY_TARGET_DEVICE_FAILED_TO_RESPOND = 11,
MODBUS_EXCEPTION_ILLEGAL_DEVICE_ID_CODE = 3
} modbus_exception_code_t;
typedef struct {
uint8_t exception_code;
} exception_t;
typedef struct {
modbus_function_code_t function_code : 8;
uint16_t register_address; // e.g. first register of A0: 0
uint16_t register_number; // e.g. first register of A0: 40001
uint8_t register_count; // number of registers to be read/written
exception_t exception;
modbus_exception_code_t exception;
uint8_t broadcast; // 1 if broadcast, 0 otherwise
union {
uint8_t buffer8b[MODBUS_MAX_RTU_FRAME_SIZE];
@ -150,6 +154,34 @@ typedef enum {
MODBUS_AO_END_NUMBER = 49999
} modbus_register_number_t;
typedef enum {
MODBUS_CONFORMITY_BASIC = 1,
MODBUS_CONFORMITY_REGULAR = 2,
MODBUS_CONFORMITY_EXTENDED = 3,
MODBUS_INDIVIDUAL_ACCESS = 4
} modbus_conformity_level_t;
/* Device ID datatypes */
#define MODBUS_DEVICE_ID_OBJECT_NUM 7
typedef struct {
union {
struct {
/* Basic category (mandatory part) */
char *VendorName;
char *ProductCode;
char *MajorMinorRevision;
/* Regular category (optional part) */
char *VendorUrl;
char *ProductName;
char *ModelName;
char *UserApplicationName;
/* Extended category (optional part) */
// Nothing here yet!
} object_name;
char *object_id[MODBUS_DEVICE_ID_OBJECT_NUM];
};
uint8_t conformity_level;
} modbus_device_id_t;
/*
* Global variables
@ -161,6 +193,9 @@ extern uint8_t modbus_slave_address;
/* shared modbus buffer; defined in modbus.c; may be used elsewhere in code */
extern uint8_t modbus_buffer[];
/* modbus device id struct */
extern modbus_device_id_t *modbus_device_id;
/*
* Function prototypes
*/
@ -172,6 +207,7 @@ extern uint8_t modbus_buffer[];
* Both functions have to be implemented by user.
*/
int8_t modbus_slave_process_msg(const uint8_t *buffer, int len);
int8_t modbus_slave_init_device_id(modbus_device_id_t *device_id);
int8_t modbus_slave_set_address(uint8_t address);
/* modbus callback function type - should be implemented by user (e.g. in main.c) */
int8_t modbus_slave_callback(modbus_transaction_t *transaction);

12
fw/Core/Src/main.c
View File

@ -108,6 +108,8 @@ uint16_t sps30_measured_data[10];
/* Struct to store the sensor config */
config_t sensor_config;
/* Device ID struct */
modbus_device_id_t device_id;
uint8_t sensor_config_pending_write = 0;
uint8_t baudrate_changed = 0;
uint8_t modbus_address_changed = 0;
@ -228,6 +230,16 @@ int main(void)
rgbled_set_intensity(sensor_config.led_brightness);
rgbled_set_color(RGBLED_WHITE); /* white color indicates init process */
/* Fill device ID struct */
device_id.object_name.VendorName = "NeoMokoshTron Corp.";
device_id.object_name.ProductCode = "124C41";
device_id.object_name.MajorMinorRevision = "1.2";
device_id.object_name.VendorUrl = "https://neomokoshtron.com";
device_id.object_name.ProductName = "SensCO2";
device_id.object_name.ModelName = "Hugo";
modbus_slave_init_device_id(&device_id);
LL_mDelay(2000);
scd4x_start_periodic_measurement();

328
fw/Core/Src/modbus.c
View File

@ -16,9 +16,12 @@
* during execution of modbus_process_message() */
uint8_t modbus_buffer[MODBUS_MAX_RTU_FRAME_SIZE];
/* device address: declared */
/* MODBUS device address */
uint8_t modbus_slave_address = MODBUS_DEFAULT_SLAVE_ADDRESS;
/* Device ID struct */
modbus_device_id_t *modbus_device_id = NULL;
/*
* CRC16 functions
* see https://modbus.org/docs/Modbus_over_serial_line_V1_02.pdf
@ -53,7 +56,7 @@ uint16_t modbus_CRC16(const uint8_t *buf, int len)
/* here we assume buffer has minimal size of MODBUS_MAX_RTU_FRAME_SIZE;
* this function is private, so hopefully it's going to be ok */
int8_t modbus_copy_reply_to_buffer(uint8_t *buffer, uint8_t *msg_len, modbus_transaction_t *transaction)
static int8_t modbus_transaction_to_buffer(uint8_t *buffer, uint8_t *msg_len, modbus_transaction_t *transaction)
{
uint16_t crc16;
uint8_t byte_count;
@ -65,7 +68,7 @@ int8_t modbus_copy_reply_to_buffer(uint8_t *buffer, uint8_t *msg_len, modbus_tra
if (transaction->function_code & MODBUS_ERROR_FLAG) {
/* sending error reply */
buffer[2] = transaction->exception.exception_code;
buffer[2] = transaction->exception;
} else {
switch (transaction->function_code) {
case MODBUS_READ_HOLDING_REGISTERS:
@ -101,6 +104,169 @@ int8_t modbus_copy_reply_to_buffer(uint8_t *buffer, uint8_t *msg_len, modbus_tra
buffer[*msg_len - 1] = crc16 >> 8;
}
static int8_t modbus_process_device_id_request(const uint8_t *buffer, int len, modbus_transaction_t *transaction)
{
uint8_t MEI_type;
uint8_t read_device_id_code;
uint8_t object_id;
uint8_t conformity_masked;
uint8_t individual_object_access;
uint8_t buffer_pos = 0;
if (transaction->broadcast == 1) {
/* Read device ID broadcast - invalid; ignore (master will get timeout) */
return MODBUS_ERROR;
}
if (modbus_device_id == NULL) {
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_DEVICE_ID_CODE;
return MODBUS_OK;
}
if (len < MODBUS_READ_DEVICE_ID_REQUEST_LEN) {
/* frame too short, ignore */
return MODBUS_ERROR;
}
/* next byte should be MEI = 0x0E */
MEI_type = buffer[buffer_pos++];
if (MEI_type != MODBUS_MEI) {
/* invalid MEI, ignore. I have no idea what this MEI does, but it should always be 0x0E */
return MODBUS_ERROR;
}
/* next byte is read device id code */
read_device_id_code = buffer[buffer_pos++];
/* read device id code can only have values 1,2,3,4 */
if (read_device_id_code < 1 || read_device_id_code > 4) {
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_DEVICE_ID_CODE;
return MODBUS_OK;
}
/* cross-check with conformity level (mask 0x80 bit, which only specified individual access) */
if (read_device_id_code == MODBUS_INDIVIDUAL_ACCESS) {
individual_object_access = 1;
} else {
/* check conformity level */
conformity_masked = modbus_device_id->conformity_level & ~0x80;
if (read_device_id_code > conformity_masked) {
/* requested conformity higher than allowed */
read_device_id_code = conformity_masked;
}
}
/* next byte is object id */
object_id = buffer[buffer_pos++];
if (object_id > MODBUS_DEVICE_ID_OBJECT_NUM) {
/* illegal object ID */
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS;
return MODBUS_OK;
}
/* Message processed; create reply message */
}
/* returns ERROR only when no response to master is needed */
static int8_t modbus_process_read_write_request(const uint8_t *buffer, int len, modbus_transaction_t *transaction)
{
uint8_t byte_count;
int8_t callback_result;
uint8_t buffer_pos = 0;
/* set starting register number */
switch (transaction->function_code) {
/* coils */
case MODBUS_READ_DO:
case MODBUS_WRITE_SINGLE_DO:
case MODBUS_WRITE_MULTIPLE_DO:
transaction->register_number = MODBUS_DO_START_NUMBER;
break;
/* discrete inputs */
case MODBUS_READ_DI:
transaction->register_number = MODBUS_DI_START_NUMBER;
break;
/* input registers */
case MODBUS_READ_AI:
transaction->register_number = MODBUS_AI_START_NUMBER;
break;
/* holding registers */
case MODBUS_READ_AO:
case MODBUS_WRITE_SINGLE_AO:
case MODBUS_WRITE_MULTIPLE_AO:
case MODBUS_READ_WRITE_MULTIPLE_REGISTERS:
transaction->register_number = MODBUS_AO_START_NUMBER;
break;
}
#define MODBUS_FLAG_WRITE 0x01
#define MODBUS_FLAG_SINGLE 0x02
uint8_t flags = 0x00;
/* process message */
switch (transaction->function_code) {
case MODBUS_WRITE_SINGLE_COIL:
case MODBUS_WRITE_SINGLE_REGISTER: /* holding register */
flags |= MODBUS_FLAG_SINGLE;
case MODBUS_WRITE_MULTIPLE_COILS:
case MODBUS_WRITE_MULTIPLE_REGISTERS:
flags |= MODBUS_FLAG_WRITE;
case MODBUS_READ_DISCRETE_INPUTS:
case MODBUS_READ_COILS:
case MODBUS_READ_INPUT_REGISTERS:
case MODBUS_READ_HOLDING_REGISTERS:
if (len < (MODBUS_MINIMAL_FRAME_LEN + 2)) {
/* buffer too short to contain everything we need */
return MODBUS_ERROR;
}
transaction->register_address = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
// TODO check length!
if (flags & MODBUS_FLAG_WRITE) {
if (flags & MODBUS_FLAG_SINGLE) {
transaction->holding_registers[0] = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
} else {
/* Write multiple registers */
transaction->register_count = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
byte_count = buffer[buffer_pos++];
if (transaction->register_count > 123 || 2*transaction->register_count != byte_count) {
/* Max number of register is defined by Modbus_Application_Protocol_V1_1b, section 6.12 */
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_REGISTER_QUANTITY;
} else {
for (uint8_t i = 0; i < transaction->register_count; i++) {
transaction->holding_registers[i] = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
}
}
}
} else {
transaction->register_count = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
if (
transaction->register_count < 1 ||
transaction->register_count > MODBUS_MAX_REGISTERS
) {
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE;
}
}
// add offset to register number
transaction->register_number += transaction->register_address;
break;
default:
/* function code not known / not implemented, reply with
* ExceptionCode 1 */
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_FUNCTION;
break;
}
/* data in modbus_buffer have been processed and buffer can be re-used for TX */
/* handle reply */
if (transaction->exception != 0) {
/* indicate error */
transaction->function_code |= MODBUS_ERROR_FLAG;
} else {
callback_result = modbus_slave_callback(transaction);
/* error handling */
if (callback_result != MODBUS_OK) {
transaction->function_code |= MODBUS_ERROR_FLAG;
if (callback_result == MODBUS_ERROR_FUNCTION_NOT_IMPLEMENTED) {
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_FUNCTION;
} else if (callback_result == MODBUS_ERROR_REGISTER_NOT_IMPLEMENTED) {
transaction->exception = MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS;
}
}
}
return MODBUS_OK;
}
/*
* Public function definitions
*/
@ -115,14 +281,19 @@ int8_t modbus_slave_set_address(uint8_t address)
return MODBUS_OK;
}
int8_t modbus_slave_process_msg(const uint8_t *buffer, int len)
{
/*
* TODO list:
*
* 1) check that errors and exceptions are handled according to Modbus_Application_Protocol_V1_1b.pdf
* 2) buffer overflow prevention: for each function code, check that buffer is long enough
*/
/* transaction holds message context and content:
* it wraps all necessary buffers and variables */
modbus_transaction_t transaction;
@ -131,135 +302,64 @@ int8_t modbus_slave_process_msg(const uint8_t *buffer, int len)
uint8_t byte_count;
if (len < MODBUS_MINIMAL_FRAME_LEN) {
/* frame too short; return error */
/* frame too short; return error (no reply needed) */
return MODBUS_ERROR_FRAME_INVALID;
}
/* check CRC first */
uint16_t crc_received = (buffer[len - 1] << 8) | buffer[len - 2];
uint16_t crc_calculated = modbus_CRC16(buffer, len - 2);
if (crc_received != crc_calculated) {
/* CRC mismatch, return error */
//printf("crc mismatch: received 0x%x, calculated 0x%x\n", crc_received, crc_calculated);
/* CRC mismatch, return error (no reply needed) */
return MODBUS_ERROR_CRC;
}
/* check if address matches ours */
uint8_t address = buffer[buffer_pos++];
if (address != modbus_slave_address && address != MODBUS_BROADCAST_ADDR) {
transaction.broadcast = (address == MODBUS_BROADCAST_ADDR);
if (address != modbus_slave_address && transaction.broadcast != 1) {
/* Message is not for us */
return MODBUS_OK;
}
/* get function code */
transaction.function_code = buffer[buffer_pos++];
transaction.exception.exception_code = 0;
transaction.exception = 0;
uint8_t request_processing_error;
if (transaction.function_code == MODBUS_READ_DEVICE_IDENTIFICATION) {
// TODO
goto modbus_send;
}
/* set starting register number */
switch (transaction.function_code) {
/* coils */
case MODBUS_READ_DO:
case MODBUS_WRITE_SINGLE_DO:
case MODBUS_WRITE_MULTIPLE_DO:
transaction.register_number = MODBUS_DO_START_NUMBER;
break;
/* discrete inputs */
case MODBUS_READ_DI:
transaction.register_number = MODBUS_DI_START_NUMBER;
break;
/* input registers */
case MODBUS_READ_AI:
transaction.register_number = MODBUS_AI_START_NUMBER;
break;
/* holding registers */
case MODBUS_READ_AO:
case MODBUS_WRITE_SINGLE_AO:
case MODBUS_WRITE_MULTIPLE_AO:
case MODBUS_READ_WRITE_MULTIPLE_REGISTERS:
transaction.register_number = MODBUS_AO_START_NUMBER;
break;
}
#define MODBUS_FLAG_WRITE 0x01
#define MODBUS_FLAG_SINGLE 0x02
uint8_t flags = 0x00;
/* process message */
switch (transaction.function_code) {
case MODBUS_WRITE_SINGLE_COIL:
case MODBUS_WRITE_SINGLE_REGISTER: /* holding register */
flags |= MODBUS_FLAG_SINGLE;
case MODBUS_WRITE_MULTIPLE_COILS:
case MODBUS_WRITE_MULTIPLE_REGISTERS:
flags |= MODBUS_FLAG_WRITE;
case MODBUS_READ_DISCRETE_INPUTS:
case MODBUS_READ_COILS:
case MODBUS_READ_INPUT_REGISTERS:
case MODBUS_READ_HOLDING_REGISTERS:
if (len < (MODBUS_MINIMAL_FRAME_LEN + 4)) {
/* buffer too short to contain everything we need */
return MODBUS_ERROR;
}
transaction.register_address = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
// TODO check length!
if (flags & MODBUS_FLAG_WRITE) {
if (flags & MODBUS_FLAG_SINGLE) {
transaction.holding_registers[0] = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
request_processing_error = modbus_process_device_id_request(buffer + buffer_pos, len - buffer_pos, &transaction);
} else {
/* Write multiple registers */
transaction.register_count = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
byte_count = buffer[buffer_pos++];
if (transaction.register_count > 123 || 2*transaction.register_count != byte_count) {
/* Max number of register is defined by Modbus_Application_Protocol_V1_1b, section 6.12 */
transaction.exception.exception_code = MODBUS_EXCEPTION_ILLEGAL_REGISTER_QUANTITY;
} else {
for (uint8_t i = 0; i < transaction.register_count; i++) {
transaction.holding_registers[i] = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
request_processing_error = modbus_process_read_write_request(buffer + buffer_pos, len - buffer_pos, &transaction);
}
}
}
} else {
transaction.register_count = (buffer[buffer_pos++] << 8) | buffer[buffer_pos++];
if (
transaction.register_count < 1 ||
transaction.register_count > MODBUS_MAX_REGISTERS
) {
transaction.exception.exception_code = MODBUS_EXCEPTION_ILLEGAL_DATA_VALUE;
}
}
// add offset to register number
transaction.register_number += transaction.register_address;
break;
default:
/* function code not known / not implemented, reply with
* ExceptionCode 1 */
transaction.exception.exception_code = MODBUS_EXCEPTION_ILLEGAL_FUNCTION;
break;
}
/* data in modbus_buffer have been processed and buffer can be re-used for TX */
/* handle reply */
if (transaction.exception.exception_code != 0) {
/* indicate error */
transaction.function_code |= MODBUS_ERROR_FLAG;
} else {
callback_result = modbus_slave_callback(&transaction);
/* error handling */
if (callback_result != MODBUS_OK) {
transaction.function_code |= MODBUS_ERROR_FLAG;
if (callback_result == MODBUS_ERROR_FUNCTION_NOT_IMPLEMENTED) {
transaction.exception.exception_code = MODBUS_EXCEPTION_ILLEGAL_FUNCTION;
} else if (callback_result == MODBUS_ERROR_REGISTER_NOT_IMPLEMENTED) {
transaction.exception.exception_code = MODBUS_EXCEPTION_ILLEGAL_DATA_ADDRESS;
}
}
}
uint8_t msg_len = 0;
modbus_send:
if (address != MODBUS_BROADCAST_ADDR) {
/* send only if master request was not broadcast */
modbus_copy_reply_to_buffer(modbus_buffer, &msg_len, &transaction);
uint8_t msg_len;
/* reply only if request was processed successfully and message was not broadcast */
if (request_processing_error == 0 && transaction.broadcast == 0) {
modbus_transaction_to_buffer(modbus_buffer, &msg_len, &transaction);
modbus_transmit_function(modbus_buffer, msg_len);
}
}
int8_t modbus_slave_init_device_id(modbus_device_id_t *device_id)
{
if (device_id == NULL) {
return MODBUS_ERROR;
}
/* at least basic category objects have to be implemented */
if ( device_id->object_name.VendorName == NULL ||
device_id->object_name.ProductCode == NULL ||
device_id->object_name.MajorMinorRevision == NULL
) {
return MODBUS_ERROR;
}
/* set conformity level: currently only "basic" and "regular" is implemented */
if ( device_id->object_id[3] != NULL &&
device_id->object_id[4] != NULL &&
device_id->object_id[5] != NULL
) {
/* strings are present in regular category (optional) */
device_id->conformity_level = MODBUS_CONFORMITY_REGULAR;
} else {
device_id->conformity_level = MODBUS_CONFORMITY_BASIC;
}
/* we support both stream and individual access to objects */
device_id->conformity_level |= MODBUS_DEVICE_ID_INDIVIDUAL_ACCESS_FLAG;
modbus_device_id = device_id;
}