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57 lines
1.2 KiB
57 lines
1.2 KiB
4 weeks ago
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/*
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* modbus_rtu.c
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*
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* Change Logs:
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* Date Author Notes
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* 2024-04-01 qiyongzhong first version
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*/
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4 weeks ago
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#include "modbus_rtu.h"
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#include "modbus_crc.h"
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#include "modbus_cvt.h"
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4 weeks ago
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#ifdef MB_USING_RTU_PROTOCOL
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int mb_rtu_frm_make(u8 *buf, const mb_rtu_frm_t *frm, mb_pdu_type_t type)//生成rtu帧, 返回帧长度
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{
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u8 *p = buf;
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p += mb_cvt_u8_put(p, frm->saddr);
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p += mb_pdu_make(p, &(frm->pdu), type);
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u16 crc = mb_crc_cal(buf, (int)(p - buf));
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*p++ = crc;
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*p++ = (crc >> 8);
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return((int)(p - buf));
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}
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int mb_rtu_frm_parse(const u8 *buf, int len, mb_rtu_frm_t *frm, mb_pdu_type_t type)//解析rtu帧, 返回pdu数据长度, 解析失败返回0, 功能码不支持返回-1
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{
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if (len < MB_RTU_FRM_MIN)
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{
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return(0);
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}
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frm->saddr = *buf;
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int remain = len - (MB_RTU_SADDR_SIZE + MB_RTU_CRC_SIZE);
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int pdu_len = mb_pdu_parse(buf + 1, remain, &(frm->pdu), type);
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if (pdu_len <= 0)
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{
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return(pdu_len);
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}
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if (remain < pdu_len)
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{
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return(0);
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}
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int flen = pdu_len + (MB_RTU_SADDR_SIZE + MB_RTU_CRC_SIZE);
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u16 cal_crc = mb_crc_cal(buf, flen);
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if (cal_crc != 0)
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{
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return(0);
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}
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return(pdu_len);
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}
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#endif
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