From 4982262f6da2cbabbe28e95de71ad6f1ce88bd94 Mon Sep 17 00:00:00 2001 From: zhji Date: Sat, 1 Jun 2024 16:18:56 +0800 Subject: [PATCH] [feat] add read function --- lark1s/lark1s.c | 330 ++++++++++++++++++++++++++++++++++++++++++++++++ lark1s/lark1s.h | 78 ++++++++++++ linux/main.c | 106 ++++++++++++++-- 3 files changed, 505 insertions(+), 9 deletions(-) create mode 100644 lark1s/lark1s.c create mode 100644 lark1s/lark1s.h diff --git a/lark1s/lark1s.c b/lark1s/lark1s.c new file mode 100644 index 0000000..eafc539 --- /dev/null +++ b/lark1s/lark1s.c @@ -0,0 +1,330 @@ +#include "lark1s.h" + +/* information register */ +#define LARK1S_REG_SN (0x0004) +#define LARK1S_SIZE_SN (8) +#define LARK1S_REG_GAS3_INFO (0x0300) +#define LARK1S_SIZE_GAS3_INFO (42) +#define LARK1S_REG_GAS3_CALI_DATA (0x032A) +#define LARK1S_SIZE_GAS3_CALI_DATA (24) +/* data register */ +#define LARK1S_REG_DATA (0x0500) +#define LARK1S_SIZE_DATA (52) +/* writable register */ +#define LARK1S_REG_GAS3_CALI_ZERO_RECORD (0x1012) +#define LARK1S_SIZE_GAS3_CALI_ZERO_RECORD (1) +#define LARK1S_REG_GAS3_CALI_SPAN_RECORD (0x1028) +#define LARK1S_SIZE_GAS3_CALI_SPAN_RECORD (1) +#define LARK1S_REG_GAS3_CALI_ACTIVE (0x103E) +#define LARK1S_SIZE_GAS3_CALI_ACTIVE (1) +#define LARK1S_REG_GAS3_CALI_RESTORE (0x1042) +#define LARK1S_SIZE_GAS3_CALI_RESTORE (1) +/* status register */ +#define LARK1S_REG_STATUS (0x0600) +#define LARK1S_SIZE_STATUS (11) + +#define MODBUS_FUNCTION_CODE_READ_INPUT (0x04) +#define MODBUS_FUNCTION_CODE_WRITE_SINGLE (0x06) +#define MODBUS_FUNCTION_CODE_WRITE_MULTI (0x10) + +#define MB_GET_HWORD(p) (uint16_t)((((uint8_t*)p)[0] << 8) | ((uint8_t*)p)[1]) +#define MB_GET_UWORD(p) (uint32_t)((((uint8_t*)p)[0] << 24) | (((uint8_t*)p)[1] << 16) | (((uint8_t*)p)[2] << 8) | ((uint8_t*)p)[3]) +#define MB_GET_SWORD(p) (int32_t)((((uint8_t*)p)[0] << 24) | (((uint8_t*)p)[1] << 16) | (((uint8_t*)p)[2] << 8) | ((uint8_t*)p)[3]) + +static volatile uint8_t mb_addr = 0x01; +static volatile uint16_t mb_errno = 0x00; + +struct crc16_result_s { + uint8_t crch; + uint8_t crcl; +}; + +static const uint8_t crc_tabl[] = { //CRC low Value Table + 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 uint8_t crc_tabh[] = { //CRC high Value Table + 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, +}; + +/* polynomial: x16+x15+x2+x1 */ +static void crc16_8005_calc(uint8_t *p, uint16_t len, struct crc16_result_s *ret) +{ + struct crc16_result_s crc = {0xFF, 0xFF}; + uint8_t i, index; + + for (i = 0; i < len; i++) { + index = crc.crcl ^ p[i]; + crc.crcl = crc.crch ^ crc_tabl[index]; + crc.crch = crc_tabh[index]; + } + ret->crcl = crc.crcl; + ret->crch = crc.crch; +} + +static int lark1s_frame_check(uint8_t *p, uint16_t len) +{ + struct crc16_result_s crc; + + if (len < 5) { + return LARK1S_PARSE_FRAME_ERROR; + } + if (p[0] != mb_addr) { + return LARK1S_PARSE_MB_ADDR_NOT_MATCH; + } + crc16_8005_calc(p, len - 2, &crc); + if (crc.crcl != p[len - 2] || crc.crch != p[len - 1]) { + return LARK1S_PARSE_CRC_ERROR; + } + return LARK1S_PARSE_OK; +} + +void lark1s_set_mb_address(uint8_t address) +{ + mb_addr = address; +} + +uint16_t lark1s_get_mb_errno(void) +{ + return mb_errno; +} + +int lark1s_req_sn(uint8_t *buffer) +{ + struct crc16_result_s crc; + int i = 0; + + buffer[i++] = mb_addr; + buffer[i++] = MODBUS_FUNCTION_CODE_READ_INPUT; + buffer[i++] = (LARK1S_REG_SN >> 8) & 0xFF; + buffer[i++] = LARK1S_REG_SN & 0xFF; + buffer[i++] = (LARK1S_SIZE_SN >> 8) & 0xFF; + buffer[i++] = LARK1S_SIZE_SN & 0xFF; + crc16_8005_calc(buffer, i, &crc); + buffer[i++] = crc.crcl; + buffer[i++] = crc.crch; + + return i; +} + +int lark1s_parse_sn(uint8_t *buffer, int length, char *sn) +{ + int ret; + int i = 0; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + i++; + if (buffer[i++] != MODBUS_FUNCTION_CODE_READ_INPUT) { + return LARK1S_PARSE_FUNCTION_CODE_ERROR; + } + if (buffer[i++] != LARK1S_SIZE_SN * 2) { + return LARK1S_PARSE_DATA_LENGTH_ERROR; + } + for (int j = 0; j < LARK1S_SIZE_SN * 2; j++) { + sn[j] = buffer[i++]; + } + + return LARK1S_PARSE_OK; +} + +int lark1s_req_gas3_info(uint8_t *buffer) +{ + struct crc16_result_s crc; + int i = 0; + + buffer[i++] = mb_addr; + buffer[i++] = MODBUS_FUNCTION_CODE_READ_INPUT; + buffer[i++] = (LARK1S_REG_GAS3_INFO >> 8) & 0xFF; + buffer[i++] = LARK1S_REG_GAS3_INFO & 0xFF; + buffer[i++] = (LARK1S_SIZE_GAS3_INFO >> 8) & 0xFF; + buffer[i++] = LARK1S_SIZE_GAS3_INFO & 0xFF; + crc16_8005_calc(buffer, i, &crc); + buffer[i++] = crc.crcl; + buffer[i++] = crc.crch; + + return i; +} + +int lark1s_parse_gas3_info(uint8_t *buffer, int length, struct lark1s_gas_info_s *info) +{ + int ret; + int i = 0; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + i++; + if (buffer[i++] != MODBUS_FUNCTION_CODE_READ_INPUT) { + return LARK1S_PARSE_FUNCTION_CODE_ERROR; + } + if (buffer[i++] != LARK1S_SIZE_GAS3_INFO * 2) { + return LARK1S_PARSE_DATA_LENGTH_ERROR; + } + info->gas_id = MB_GET_UWORD(buffer + i); + for (int j = 0; j < 12; j++) { + info->gas_name[j] = buffer[i + 4 + j]; + } + info->unit_id = MB_GET_UWORD(buffer + i + 16); + for (int j = 0; j < 8; j++) { + info->unit_name[j] = buffer[i + 20 + j]; + } + info->range = MB_GET_UWORD(buffer + i + 32); + info->min_cali = MB_GET_UWORD(buffer + i + 56); + + return LARK1S_PARSE_OK; +} + +int lark1s_req_data(uint8_t *buffer) +{ + struct crc16_result_s crc; + int i = 0; + + buffer[i++] = mb_addr; + buffer[i++] = MODBUS_FUNCTION_CODE_READ_INPUT; + buffer[i++] = (LARK1S_REG_DATA >> 8) & 0xFF; + buffer[i++] = LARK1S_REG_DATA & 0xFF; + buffer[i++] = (LARK1S_SIZE_DATA >> 8) & 0xFF; + buffer[i++] = LARK1S_SIZE_DATA & 0xFF; + crc16_8005_calc(buffer, i, &crc); + buffer[i++] = crc.crcl; + buffer[i++] = crc.crch; + + return i; +} + +int lark1s_parse_data(uint8_t *buffer, int length, struct lark1s_data_s *data) +{ + int ret; + int i = 0; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + i++; + if (buffer[i++] != MODBUS_FUNCTION_CODE_READ_INPUT) { + return LARK1S_PARSE_FUNCTION_CODE_ERROR; + } + if (buffer[i++] != LARK1S_SIZE_DATA * 2) { + return LARK1S_PARSE_DATA_LENGTH_ERROR; + } + data->det_temp = MB_GET_UWORD(buffer + i); + data->air_pressure = MB_GET_UWORD(buffer + i + 8); + data->cts_ref = MB_GET_UWORD(buffer + i + 36); + data->gas3_reading = MB_GET_UWORD(buffer + i + 64); + data->cts_gas3 = MB_GET_UWORD(buffer + i + 68); + data->gas3_compensated_reading = MB_GET_SWORD(buffer + i + 104); + + return LARK1S_PARSE_OK; +} + +int lark1s_req_gas3_cali_zero_record(uint8_t *buffer); +int lark1s_parse_gas3_cali_zero_record(uint8_t *buffer, int length) +{ + int ret; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + + return LARK1S_PARSE_OK; +} + +int lark1s_req_gas3_cali_span_record(uint8_t *buffer, uint32_t concentration); +int lark1s_parse_gas3_cali_span_record(uint8_t *buffer, int length) +{ + int ret; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + + return LARK1S_PARSE_OK; +} + +int lark1s_req_gas3_cali_active(uint8_t *buffer); +int lark1s_parse_gas3_cali_active(uint8_t *buffer, int length) +{ + int ret; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + + return LARK1S_PARSE_OK; +} + +int lark1s_req_gas3_cali_restore(uint8_t *buffer); +int lark1s_parse_gas3_cali_restore(uint8_t *buffer, int length) +{ + int ret; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + + return LARK1S_PARSE_OK; +} + +int lark1s_req_status(uint8_t *buffer); +int lark1s_parse_status(uint8_t *buffer, int length, struct lark1s_status_s *status) +{ + int ret; + + ret = lark1s_frame_check(buffer, length); + if (ret) { + return ret; + } + + return LARK1S_PARSE_OK; +} diff --git a/lark1s/lark1s.h b/lark1s/lark1s.h new file mode 100644 index 0000000..c0f234a --- /dev/null +++ b/lark1s/lark1s.h @@ -0,0 +1,78 @@ +#ifndef __LARK1S_H__ +#define __LARK1S_H__ + +#include "stdint.h" + +#define LARK1S_PARSE_OK (0) +#define LARK1S_PARSE_MB_ADDR_NOT_MATCH (1) +#define LARK1S_PARSE_FUNCTION_CODE_ERROR (2) +#define LARK1S_PARSE_FRAME_ERROR (3) +#define LARK1S_PARSE_CRC_ERROR (4) +#define LARK1S_PARSE_DATA_LENGTH_ERROR (5) + +struct lark1s_gas_info_s { + uint32_t gas_id; + uint8_t gas_name[12]; + uint32_t unit_id; + uint8_t unit_name[8]; + uint32_t range; + uint32_t min_cali; +}; + +struct lark1s_gas_cali_data_s { + uint32_t available; + uint32_t zero_sig_cts; + uint32_t zero_ref_cts; + uint32_t zero_det_temp; + uint32_t zero_lamp_temp; + uint32_t span_concentration; + uint32_t span_sig_cts; + uint32_t span_ref_cts; + uint32_t span_det_temp; + uint32_t span_lamp_temp; +}; + +struct lark1s_data_s { + uint32_t det_temp; + uint32_t air_pressure; + uint32_t gas3_reading; + uint32_t cts_ref; + uint32_t cts_gas3; + int32_t gas3_compensated_reading; +}; + +struct lark1s_status_s { + uint16_t zero_record[4]; + uint16_t span_record[4]; + uint16_t active; + uint16_t restore; +}; + +#ifdef __cplusplus + extern "C" { +#endif + +void lark1s_set_mb_address(uint8_t address); +uint16_t lark1s_get_mb_errno(void); +int lark1s_req_sn(uint8_t *buffer); +int lark1s_parse_sn(uint8_t *buffer, int length, char *sn); +int lark1s_req_gas3_info(uint8_t *buffer); +int lark1s_parse_gas3_info(uint8_t *buffer, int length, struct lark1s_gas_info_s *info); +int lark1s_req_data(uint8_t *buffer); +int lark1s_parse_data(uint8_t *buffer, int length, struct lark1s_data_s *data); +int lark1s_req_gas3_cali_zero_record(uint8_t *buffer); +int lark1s_parse_gas3_cali_zero_record(uint8_t *buffer, int length); +int lark1s_req_gas3_cali_span_record(uint8_t *buffer, uint32_t concentration); +int lark1s_parse_gas3_cali_span_record(uint8_t *buffer, int length); +int lark1s_req_gas3_cali_active(uint8_t *buffer); +int lark1s_parse_gas3_cali_active(uint8_t *buffer, int length); +int lark1s_req_gas3_cali_restore(uint8_t *buffer); +int lark1s_parse_gas3_cali_restore(uint8_t *buffer, int length); +int lark1s_req_status(uint8_t *buffer); +int lark1s_parse_status(uint8_t *buffer, int length, struct lark1s_status_s *status); + +#ifdef __cplusplus +} +#endif + +#endif /* __LARK1S_H__ */ diff --git a/linux/main.c b/linux/main.c index 99b19a3..093b41e 100644 --- a/linux/main.c +++ b/linux/main.c @@ -5,8 +5,100 @@ #include #include #include +#include "../lark1s/lark1s.h" -int main() { +#define MB_ADDRESS 9 +#define MB_RESP_TIME 1 +#define BUFFER_SIZE 1024 +uint8_t buffer_w[BUFFER_SIZE]; +uint8_t buffer_r[BUFFER_SIZE]; + +void print_sn(int fd, uint8_t *out, uint8_t *in) +{ + uint8_t sn[16]; + int ret; + + ret = lark1s_req_sn(out); + if (ret) { + write(fd, out, ret); + } else { + printf("Error: lark1s_req_sn failed\r\n"); + } + sleep(MB_RESP_TIME); + ret = read(fd, in, BUFFER_SIZE); + ret = lark1s_parse_sn(in, ret, sn); + if (ret) { + printf("Error: lark1s_parse_sn failed, %d\r\n", ret); + } else { + printf("SN: "); + for (int j = 0; j < 16; j++) { + printf("%c", sn[j]); + } + printf("\r\n"); + } +} + +void print_gas3_info(int fd, uint8_t *out, uint8_t *in) +{ + struct lark1s_gas_info_s info; + int ret; + + ret = lark1s_req_gas3_info(out); + if (ret) { + write(fd, out, ret); + } else { + printf("Error: lark1s_req_gas3_info failed\r\n"); + } + sleep(MB_RESP_TIME); + ret = read(fd, in, BUFFER_SIZE); + ret = lark1s_parse_gas3_info(in, ret, &info); + if (ret) { + printf("Error: lark1s_parse_gas_info failed, %d\r\n", ret); + } else { + printf("gas3_info.gas_id: %d\r\n", info.gas_id); + printf("gas3_info.gas_name: "); + for (int j = 0; j < 12; j++) { + printf("%c", info.gas_name[j]); + } + printf("\r\n"); + printf("gas3_info.unit_id: %d\r\n", info.unit_id); + printf("gas3_info.unit_name: "); + for (int j = 0; j < 8; j++) { + printf("%c", info.unit_name[j]); + } + printf("\r\n"); + printf("gas3_info.range: %d\r\n", info.range); + printf("gas3_info.min_cali: %d\r\n", info.min_cali); + } +} + +void print_data(int fd, uint8_t *out, uint8_t *in) +{ + struct lark1s_data_s data; + int ret; + + ret = lark1s_req_data(out); + if (ret) { + write(fd, out, ret); + } else { + printf("Error: lark1s_req_data failed\r\n"); + } + sleep(MB_RESP_TIME); + ret = read(fd, in, BUFFER_SIZE); + ret = lark1s_parse_data(in, ret, &data); + if (ret) { + printf("Error: lark1s_parse_data failed, %d\r\n", ret); + } else { + printf("data.det_temp: %d\r\n", data.det_temp); + printf("data.air_pressure: %d\r\n", data.air_pressure); + printf("data.gas3_reading: %d\r\n", data.gas3_reading); + printf("data.cts_ref: %d\r\n", data.cts_ref); + printf("data.cts_gas3: %d\r\n", data.cts_gas3); + printf("data.gas3_compensated_reading: %d\r\n", data.gas3_compensated_reading); + } +} + +int main(void) { int fd; struct termios options; @@ -25,16 +117,12 @@ int main() { tcflush(fd, TCIFLUSH); tcsetattr(fd, TCSANOW, &options); - uint8_t buffer_w[] = {0x09, 0x04, 0x00, 0x00, 0x00, 0x20, 0xF0, 0x9A}; - uint8_t buffer_r[256]; + lark1s_set_mb_address(MB_ADDRESS); while (1) { - write(fd, buffer_w, sizeof(buffer_w)); - sleep(1); + print_sn(fd, buffer_w, buffer_r); + print_gas3_info(fd, buffer_w, buffer_r); + print_data(fd, buffer_w, buffer_r); - int num_bytes = read(fd, buffer_r, sizeof(buffer_r)); - for (int i = 0; i < num_bytes; i++) { - printf("%02X ", buffer_r[i]); - } printf("\r\n"); fflush(stdout); }