python 串口通信对激光测距模块的简单测试，备用于互动项目，pc上位机 ，移植到单片机皆可
模块基本情况
型号：SK-Z-5 量程：0.06-5m
型号：SK-Z-10 量程：0.06-10m
型号：SK-Z-20 量程：0.06-20m
输出频率：50/100/200Hz 典型输出频率：100Hz
重复精度：±2cm（2m内） 精度：1-10cm
显示单位：1mm 光源：780nm激光 I类安全
规格尺寸：20*22*14mm 不可见红色激光
重量：11g 电源：DC+5V
输出接口：串口TTL 电平：3.3V
工作温度：-10~+60℃ 抗环境光：100W LUX
通信接口文档
理解协议
串口115200波特率，readline接收呗
如接收到数据
7e 30 31 30 33 30 31 30 30 30 31 39 41 43 35 43 44
当作字符串来看待
19个字符为一个包
~01030100019ac5cd\r\n
起始 1个字符
设备地址2个字符
命令码2个字符
寄存器地址H 2个字符
寄存器地址L 2个字符
数据H 2个字符
数据L 2个字符
CRCL 2个字符
CRCH 2个字符
结束符2个字符
分割为
~ 01 03 01 00 01 9a c5 cd \r \n
去掉起始字符和结尾后剩余转换为16进制数据
01 03 01 00 01 9a 的crc校验值为c5 cd
主要变换就是两个字符转换为一个字节
上python源码
#print(len(rcv))
data_len=len(rcv)
data_list=[0 for i in range(8)]
if(data_len==19 ):
print("recv:")
'''
str_=rcv[0]
str_dvcid=rcv[1:3]
str_cmd= rcv[3:5]
str_jcq_H= rcv[5:7]
str_jcq_L = rcv[7:9]
str_data_H = rcv[9:11]
str_data_L = rcv[11:13]
str_crc_L = rcv[13:15]
str_crc_H = rcv[15:17]
str_rn = rcv[17:]
'''
list_index=0
for i in range(1, data_len-2,2):
#print(rcv[i:i+2])
data_list[list_index] = int(rcv[i:i+2].decode('ascii'),16)
list_index+=1
#print(data_list)
data_count_crc = data_list[0:7]
# print(data_count_crc)
# 计算crc
crc16=serails_jiguang_crc_modbus.CRC16(data_count_crc,6)
#crc 低8位在前
#print(data_list[6], data_list[7])
#print((crc16>>8)&0xff,crc16&0xff)
#比对crc
if(crc16==((data_list[6]<<8)| data_list[7])):
#print(data_list[4], data_list[5])
print(data_list[4]<<8| data_list[5])#距离数据
self.count+=1
else:
print("check data err")
else:
print("data length err")
其中有crc校验没有使用现成的库移植了网上前辈们的代码做了个试验，有查表法和按部就班法，代码写一块了
auchCRCHi=[
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
]
auchCRCLo=[
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
]
'''
/*
*function：unsigned int CRC16(unsigned char *puchMsg,unsigned int usDataLen)
*decription: 计算CRC校验码
'''
def CRC16(puchMsg,usDataLen):
# unsigned char
uchCRCHi=0
uchCRCLo=0
uIndex=0 #/* will index into CRC lookup table */
tempp=0
# unsigned int
CRCHL=0
uchCRCHi=0xFF #// high byte of CRC initialized
uchCRCLo=0xFF #// low byte of CRC initialized
tempp=0
while(usDataLen):
usDataLen -=1
uIndex=uchCRCHi ^ puchMsg[tempp]
tempp+=1
uchCRCHi=uchCRCLo ^ auchCRCHi[uIndex] # // calculate the CRC high bytev #//01-auchCRCHi[254]:0x81;02-0x01;03-0x80;04-0xC0
uchCRCLo=auchCRCLo[uIndex]
#print(tempp)
CRCHL=uchCRCHi
CRCHL=CRCHL<<8
CRCHL|=uchCRCLo
return CRCHL #//(uchCRCHi<<8|uchCRCLo) ;//uchCRCHi:0xa1;uchCRCLo:2B
def crc16_modbus(buff,length):
n = 0
tmp = 0xffff
while( n < length): #/*此处的length -- 要校验的位数为length个*/
tmp = buff[n] ^ tmp
i=0
while(i < 8): # /*此处的8 -- 指每一个char类型又8bit，每bit都要处理*/
if(tmp & 0x01):
tmp = tmp >> 1
tmp = tmp ^ 0xa001
else:
tmp = tmp >> 1
i+=1
n+=1
#print(n)
ret1 = ((tmp >> 8)&0xff)| ((tmp << 8)&0xff00)
return ret1
if __name__ == "__main__":
CRCx = CRC16([0x01,0x03,0x08 ,0x00, 0x01 ,0x00 ,0x01, 0x00, 0x01, 0x00, 0x01],11)
print('0x%x'%(CRCx>>8))
print('0x%x'%(CRCx &0xff))
print('-----------')
CRCx = crc16_modbus([0x01,0x03,0x08 ,0x00, 0x01 ,0x00 ,0x01, 0x00, 0x01, 0x00, 0x01],11)
print('0x%x' % (CRCx ))
print('0x%x' % (CRCx >> 8))
print('0x%x' % (CRCx & 0xff))
print('-----------')
CRCx = CRC16([0x01,0x03,0x00,0x00,0x00,0x01],6)
print('0x%x' % (CRCx >> 8))
print('0x%x' % (CRCx & 0xff))
print('-----------')
CRCx = crc16_modbus([0x01,0x03,0x00,0x00,0x00,0x01],6)
print('0x%x' % (CRCx >> 8))
print('0x%x' % (CRCx & 0xff))
对crc的算法，以及查表法表的由来展开了一些搜索，
参考如下
Modbus CRC16校验算法--查表法
https://blog.csdn.net/dmfylb/article/details/73829271
Modbus RTU CRC计算器
http://cht.nahua.com.tw/index.php?url=http://cht.nahua.com.tw/software/crc16/&key=Modbus,%20RTU,%20CRC16&title=%E8%A8%88%E7%AE%97%20Modbus%20RTU%20CRC16
CRC-16 / MODBUS 校验计算方法
https://blog.csdn.net/u013625451/article/details/81239572
CRC16常见几个标准的算法及C语言实现
https://blog.csdn.net/u010144805/article/details/80803572
CRC查表法——表的由来
http://www.xjtudll.cn/Exp/273/
CRC查找表法推导及代码实现比较
https://blog.csdn.net/huang_shiyang/article/details/50881305
CRC算法 个人学习笔记 直接法、查表法注意点
https://blog.csdn.net/bobde163/article/details/78760213
