- \n
- \u3010MSP430\u958b\u767c\u65e5\u8a8c\u3011UART\u5ef6\u4f38\u61c9\u7528RS485(MAX485\u6a21\u7d44) \u2013 \u524d\u8a00\u8207\u6e96\u5099<\/a><\/li>\n<\/ul>\n
\u6700\u5f8c\u7684\u8173\u4f4d\u5c0d\u61c9\u70ba<\/p>\n
RO => RXD = D5\r\nDI => TXD = D6\r\nTR = D2<\/pre>\n
--<\/p>\n
SoftwareSerial<\/h2>\n
\u56e0\u70ba\u4f7f\u7528\u4e86 UART \u8f49 RS485 \u5c0f\u677f\uff0c\u56e0\u6b64\u53ea\u8981\u8a2d\u5b9a\u597d\u9b91\u7387\u3001\u50b3\u9001\u7684\u8cc7\u6599\u53ca\u8a08\u7b97 CRC \u5373\u53ef<\/p>\n
- \n
- ESP8266 Two Serial Ports With SoftwareSerial Library<\/a><\/li>\n<\/ul>\n
#include <SoftwareSerial.h>\r\n\r\nSoftwareSerial mySerial(14, 12); \/\/ RX, TX\r\n\r\n#define DE 4 \/\/ D6\u4f7f\u80fd\u767c\u9001\u5668\uff0c\u9ad8\u96fb\u5e73\u6709\u6548\r\n\r\nvoid setup()\r\n{\r\n pinMode(not_RE, OUTPUT);\r\n pinMode(DE, OUTPUT);\r\n digitalWrite(not_RE, HIGH); \/\/ disable receiver\r\n digitalWrite(DE, HIGH); \/\/ enable transmitter\r\n\r\n Serial.begin(57600);\r\n mySerial.begin(9600);\r\n}\r\n\r\nvoid loop()\r\n{\r\n Serial.println(\"aaa\");\r\n mySerial.println(\"aaa\");\r\n delay(100);\r\n}<\/pre>\n--<\/p>\n
CRC<\/h2>\n
- \n
- Arduino and RS485 communication<\/a><\/li>\n<\/ul>\n
uint16_t CalcCRC(byte * data, uint8_t datlen) {\r\n uint16_t CRC = 0xFFFF; \/\/ Init CRC\r\n uint8_t xor_flag;\r\n for (uint8_t n = 0; n < datlen; n++) {\r\n CRC = CRC ^ data[n];\r\n for (uint8_t i = 0; i < 8; i++) {\r\n if (CRC & 0x0001) {\r\n xor_flag = 1;\r\n }\r\n else {\r\n xor_flag = 0;\r\n }\r\n CRC = CRC >> 1;\r\n if (xor_flag) {\r\n CRC = CRC ^ 0xA001;\r\n }\r\n }\r\n }\r\n return CRC;\r\n}\r\n\r\nvoid SendCmd( byte * data, uint8_t datlen) { \/\/ this is just a test routine to send results Serial Monitor.\r\n uint16_t CRC = CalcCRC(data, datlen);\r\n for (uint8_t i = 0; i < datlen; i++) { \/\/ set TX mode, use the correct Serial (softSerial?)\r\n Serial.print(data[i], HEX);\r\n Serial.print(' ');\r\n }\r\n Serial.print(lowByte(CRC), HEX); \/\/ This does not match the Example. It could be an error in the manual.\r\n Serial.print(' '); \/\/ If the device does not respond, reverse the order byte order the CRC\r\n Serial.println(highByte(CRC), HEX); \/\/ is sent. Send highbyte then lowByte.\r\n}<\/pre>\n\u4ee5\u00a0{0x01, 0x03, 0x00, 0x00, 0x00, 0x02} \u70ba\u4f8b\uff0c\u7b97\u51fa\u4f86\u61c9\u8a72\u662f 0xC4, 0x0B \u624d\u5c0d<\/p>\n
--<\/p>\n
\u786c\u9ad4\u63a5\u7dda<\/h2>\n
![\"\"](\"https:\/\/blog.hoyo.idv.tw\/wp-content\/uploads\/2020\/12\/IMG_20201217_143233-225x300.jpg\")
<\/a>\u6b63\u9762<\/figcaption><\/figure>\n ![\"\"](\"https:\/\/blog.hoyo.idv.tw\/wp-content\/uploads\/2020\/12\/IMG_20201217_143247-225x300.jpg\")
<\/a>\u80cc\u9762<\/figcaption><\/figure>\n --<\/p>\n
\u7a0b\u5f0f\u7bc4\u4f8b<\/h2>\n
#include <SoftwareSerial.h>\r\n\r\nSoftwareSerial rs485;\r\n\r\n#define DE 4\r\n\r\nbyte s[] = {0x60, 0x03, 0x00, 0x00, 0x00, 0x10};\r\nbyte r[sizeof(s) + 2];\r\n\r\nuint16_t CalcCRC(byte * data, uint8_t datlen) {\r\n uint16_t CRC = 0xFFFF; \/\/ Init CRC\r\n uint8_t xor_flag;\r\n for (uint8_t n = 0; n < datlen; n++) {\r\n CRC = CRC ^ data[n];\r\n for (uint8_t i = 0; i < 8; i++) {\r\n if (CRC & 0x0001) {\r\n xor_flag = 1;\r\n }\r\n else {\r\n xor_flag = 0;\r\n }\r\n CRC = CRC >> 1;\r\n if (xor_flag) {\r\n CRC = CRC ^ 0xA001;\r\n }\r\n }\r\n }\r\n return CRC;\r\n}\r\n\r\nvoid printHex(uint8_t num) {\r\n char hexCar[2];\r\n sprintf(hexCar, \"%02X\", num);\r\n Serial.print(hexCar);\r\n}\r\n\r\nvoid setup()\r\n{\r\n pinMode(DE, OUTPUT);\r\n Serial.begin(9600);\r\n rs485.begin(2400, SWSERIAL_8N1, 14, 12);\r\n\r\n for ( int i = 0; i < sizeof(s); i++ ) {\r\n r[i] = s[i];\r\n }\r\n}\r\n\r\nvoid loop()\r\n{\r\n digitalWrite(DE, HIGH);\r\n\r\n uint16_t CRC = CalcCRC(s, 6);\r\n r[6] = lowByte(CRC);\r\n r[7] = highByte(CRC);\r\n\r\n rs485.write(r, sizeof(r));\r\n\r\n digitalWrite(DE, LOW);\r\n delay(300);\r\n\r\n for ( int i = 0; i < sizeof(r); i++ ) {\r\n printHex(r[i]);\r\n }\r\n Serial.println();\r\n\r\n if (rs485.available() > 0)\r\n {\r\n while (rs485.available() > 0)\r\n {\r\n Serial.print(rs485.read());\r\n Serial.print(',');\r\n yield();\r\n }\r\n Serial.println();\r\n }\r\n delay(1000);\r\n\r\n}<\/pre>\n\u904b\u884c\u7d50\u679c<\/p>\n
- Arduino and RS485 communication<\/a><\/li>\n<\/ul>\n
- ESP8266 Two Serial Ports With SoftwareSerial Library<\/a><\/li>\n<\/ul>\n
![\"\"](\"https:\/\/blog.hoyo.idv.tw\/wp-content\/uploads\/2020\/12\/20201204_155528-300x154.png\")
<\/a><\/p>\n