interface.c

AVR单片机,STK500下载线制作全套资料,包括程序,电路图

/**	\file 
	<b>USB receive and transmit</b><br>
	Autor: Matthias Wei遝r<br>
	Copyright 2005: Matthias Wei遝r<br>
	License: QPL (see license.txt)
	<hr>
*/
#include "stk500.h"

unsigned char checksum;

//#ifdef CONFIG_INTERFACE_USB
#if 0

	//Hardware
	#define	USB_TXE		(PINB&BIT6_POS)
	#define	USB_RXF		(PINC&BIT3_POS)
	#define	USB_RD_ON	PORTC&=BIT1_NEG
	#define	USB_RD_OFF	PORTC|=BIT1_POS
	#define	USB_WR_ON	PORTC|=BIT2_POS
	#define	USB_WR_OFF	PORTC&=BIT2_NEG
	
	/**
		Initializes the usb interface
	*/
	void interface_init(void)
	{
		PORTC |= BIT1_POS;			//USB_RD inactive
		DDRC |= BIT1_POS|BIT2_POS;	//USB_RD, USB_WR as output
	}
	
	/**
		Reads a byte from the USB interface
		
		@return received character or -1 if no character has been received
	*/
	signed int interface_getc(void)
	{
		unsigned char t;
		
		if(!USB_RXF)
		{	
			USB_RD_ON;
			asm("NOP");
			t = PIND;
			USB_RD_OFF;
			
			return t;
		}
		else return -1;
	}
	
	/**
		Writes a byte to the USB
		
		@param t Byte to be written	
	*/
	void interface_putc(unsigned char t)
	{
		while(USB_TXE);
		
		//PORTD auf Ausgang
		DDRD = 0xFF;
		//Daten auf den Port
		PORTD = t;
		
		USB_WR_ON;
		USB_WR_OFF;
		
		//PORTC auf Eingang
		DDRD = 0x00;
		//Pull-Ups ein
		PORTD = 0xFF;
		
		checksum ^= t;
	}
	
#endif

#ifdef CONFIG_INTERFACE_RS232
	
/**
	Initializes the rs232 interface
	3.6864MHz
	Autor: Lukas Salzburger
*/
void interface_init(void) {
	#ifndef __iom88v_h				/*meag8*/
		UCSRB =  (1<<RXEN) | (1<<TXEN);
		UBRRL = 1;
		UBRRH = 0;
	#else							/*mega88*/
		UCSR0B =  (1<<RXEN0) | (1<<TXEN0);
		UBRR0L = 1;
		UBRR0H = 0;
	#endif
}

/**
	Reads a byte from the UART interface
	
	Autor: Lukas Salzburger
	
	@return received character or -1 if no character has been received
*/
signed int interface_getc(void) {	/*获取PC机发来的一字节信息*/

	#ifndef __iom88v_h				/*meag8*/
		if (UCSRA & (1<<RXC)) {
			return UDR;
			}
		else {
			return -1;
			}
	#else							/*mega88*/
		if (UCSR0A & (1<<RXC0)) {
			return UDR0;
			}
		else {
			return -1;
			}
	#endif
}

/**
	Writes a byte to the UART
	
	Autor: Lukas Salzburger
	
	@param t Byte to be written	
*/
void interface_putc(unsigned char t) {

	#ifndef __iom88v_h				/*meag8*/
		while (!(UCSRA & (1<<UDRE)));
		
		UDR = t;
		checksum ^= t;
	#else							/*mega88*/
		while (!(UCSR0A & (1<<UDRE0)));
		
		UDR0 = t;
		checksum ^= t;
	#endif
}

#endif
	
/**
	Writes a string to USB
	
	@param s The string to be send
*/
void interface_print(unsigned char *s)
{
	while(*s)
	{
		interface_putc(*s);
		s++;
	}
}

/**
	Sends a 16 bit value over the USB
	MSB first
	
	@param t Value to be send
*/
void interface_put16(unsigned int t)
{
	interface_putc((t>>8)&0xFF);
	interface_putc((t>>0)&0xFF);
}

/**
	Resets the checksum accumulator
*/
void interface_reset_check(void)
{
	checksum=0;
}

/**
	Sends the accumulated checksum
*/
void interface_send_check(void)
{
	interface_putc(checksum);
	checksum=0;
}