Manual

RS485 CAN Shield User Manual
6
Rev: V1.4, Date: May 19
th
2015
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 D8(PA_9), D2(PA_10) are the sending and receiving port of RS485.
 D7(PA_8) is for RS485 sending or receiving enable. High level is for sending, low level is for
receiving.
 Message is sent to serial port of PC through D0 and D1.
 The CANH and CNAL of one CAN port should be connected to another’s CANH and CANL port,
and the A and B port of one RS485 should be connected to another’s A and B.
2.3.1. Sending side pr ogram description
CAN: After related registers are initiated. the message to be sent will be saved into the Mailbox, and
then it will be sent by driver functions.
RS485: Set RS485_E to high level, which will make RS485 into sending status. Messages will be sent
through RS485 serial port.
#include "mbed.h"
#include "CAN.h"
Serial pc(D1,D0); //serial print message
Serial RS485(D8, D2); //RS485_TX RS485_RX
DigitalOut RS485_E(D7); //RS485_E
CanTxMsg TxMessage;
uint8_t TransmitMailbox = 0;
int i =0,j=0;
int main() {
CAN_Config();//CAN initiation
RS485_E = 1;//enable RS485 sending status
/* TxMessage */ //Setting message of Txmessage
TxMessage.StdId = 0x10;
TxMessage.ExtId = 0x1234;
TxMessage.RTR=CAN_RTR_DATA;
TxMessage.IDE=CAN_ID_STD;
TxMessage.DLC=8;
TxMessage.Data[0] = 'C';
TxMessage.Data[1] = 'A';
TxMessage.Data[2] = 'N';
TxMessage.Data[3] = ' ';
TxMessage.Data[4] = 'T';