/*************************************************
 *  Copyright (C) 1999-2004 by  ZiLOG, Inc.
 *  All Rights Reserved
 *************************************************/

#include <eZ8.h>
#include <stdio.h>
#include <sio.h> // non-standard I/O
#include "main.h"
#include "uart.h"

char	rx[7]=0;
char	*rxptr;
char	rxmax=0;
char	rxready=0;

//////////////////////////////////////////////////////////
//Interrupt routine
//
// Transmission format: stx + motor + command + parameter+ chksum
// stx = 0x02
// cksum = 7 bit checksum, bit 7 always high
// motor= 2 bytes
// command = 1 byte
// parameter = 2 bytes
// total : 7 bytes 

#pragma interrupt
void isr_uart0_rx(void) 
{
char header;
char rxcom;
char unsigned chksum;

	// service Rx when system is ready
if(rxready==0)
	{
		rxcom=getchar();		// read sio
		if(rxcom==2) 			// Stx? (02)
		{
			rxptr=rx;			//Start of transmission
			rxmax=0;			//reset Rx buffer pointer
		}
		else
		{	
			rxmax++;
			*rxptr=rxcom;		// store rx character
			rxptr++;
			if(rxmax==6) 		// 7 charcters read?
			{
				chksum=2+rx[0]+rx[1]+rx[2]+rx[3]+rx[4];
				chksum=chksum | 0x80;
				if(chksum==rx[5])
					rxready=1;		// indicate buffer is ready
					else
					rxready=2;		//checksum error
				rxptr=rx;		// reset pointers
				rxmax=0;
			}
		}
	}

}

//////////////////////////////////////////////////////////
//Intialize UART 0 
void init_uart0(void)
{
    init_uart(_UART0,_DEFFREQ,BAUD_115200); // Setup Uart0 
    select_port(_UART0);				 // Select port
	SET_VECTOR(UART0_RX, isr_uart0_rx);  // Define interrupt routine
	IRQ0ENH |= 0x10;					// Set Interrupt Priority High
	IRQ0ENL |= 0x10;					// Set Interrupt Priority High
}