rs485.c

本代码为SPI/I2C转双串口驱动程序。开发环境为Keil c51.

//-----------------------------------------------
//www.zlgmcu.com
//-----------------------------------------------

#include "sc16is752.h"

//-----------------------------
//Multidrop mode
//-----------------------------

void Multidrop()
{

	WriteRegister(LCR,ChannelA,0x2B);	//0011 1011, set parity
										//Paritybit bit5=1: Address byte
										//Paritybit bit5=0: Data byte
	WriteRegister(MCR,ChannelA,0x02);	//Force RTS low level

	WriteRegister(EFCR,ChannelA,0x31);	//0011 0001 , 485 RTS control,Enable 485
	WriteRegister(FCR,ChannelA,0x06);	//enable ,reset FIFO
	WriteRegister(FCR,ChannelA,0x01);	//enable  FIFO	


//	WriteRegister(IER,ChannelA,0x04);	//0000 0100	Enable line interrupt	

}


//-----------------------------
//Auto address mode
//-----------------------------
void AutoAddress(char Address)
{
	WriteRegister(LCR,ChannelA,0xBF);	//Enter enhance mode		
	WriteRegister(EFR,ChannelA,0x20);
	WriteRegister(Xoff2,ChannelA,Address);


	WriteRegister(LCR,ChannelA,0x3B);	//0011 1011, set parity
										//Paritybit bit5=1: Address byte
										//Paritybit bit5=0: Data byte
	WriteRegister(MCR,ChannelA,0x02);	//Force RTS low level

	WriteRegister(EFCR,ChannelA,0x31);	//0011 0001 , 485 RTS control,Enable 485

	WriteRegister(FCR,ChannelA,0x06);	//enable ,reset FIFO
	WriteRegister(FCR,ChannelA,0x01);	//enable  FIFO	

//	WriteRegister(IER,ChannelA,0x04);	//0000 0100	Enable line interrupt	
}