uart.c

interface usb microcontroller with pc

//*************************************************************************
//
//                  P H I L I P S   P R O P R I E T A R Y
//
//           COPYRIGHT (c)   2004 BY PHILIPS SEMICONDUCTORS
//                     --  ALL RIGHTS RESERVED  --
//
// File Name:	uart.c
// Created:		April 16, 2004
// Modified:	Handoko (Hans) Chendra
// Revision: 	1.00
//
//*************************************************************************

#include <REG51RX.H>		// special function register declarations
#include "uart.h"

void Uart_Write(unsigned char Reg, unsigned char val) // Reg = register to be written, val = value
{
	// UART address
   A0 = Reg & 0x01;
	A1 = Reg & 0x02;
	A2 = Reg & 0x04;
	A3 = Reg & 0x08;	
	
	UART_CEN = 0;	// enable the UART
	
	// write data to the microcontroller data bus
	AUXR = 0x02;	// access external memory, emit/don't emit ALE --> emit when using emulator
	*((unsigned char pdata *)MCU_COMMAND) = val;
	AUXR = 0x00;	// access internal memory, emit ALE when using emulator

	UART_CEN = 1;	// disable the UART
}

unsigned char Uart_Read(unsigned char Reg)  // Reg = register to be written
{
	unsigned char RegData;
	int i;

   // UART address
   A0 = Reg & 0x01;
   A1 = Reg & 0x02;
   A2 = Reg & 0x04;
	A3 = Reg & 0x08;
	   
	UART_CEN = 0;	// enable the UART
	
   // read data from the microcontroller data bus
	AUXR = 0x02;	// access external memory, emit ALE when using emulator
	RegData = *((unsigned char pdata *)MCU_COMMAND);
	AUXR = 0x00;	// access internal memory, emit ALE when using emulator
	
	UART_CEN = 1;	// disable the UART
		
	return RegData;
}

void Uart_Reset(void)
{
	int i;
	UART_Reset = 1;      // enable UART reset
	for (i=0;i<10;i++);  // delay
	UART_Reset = 0; 		// disable UART reset
}