main.c

使用STC单片机的SPI控制器读写FRAM的程序

//-----------------------------------------------------------------------------
// MAIN.C
//-----------------------------------------------------------------------------
// Author  Zhou Ke
// Email   [e-mail]
// Target:         FRAM_UART
// Tool chain:     Keil C51 8.02 / Keil EVAL C51
// Project Name:   FRAM_UART
//
//
// Release 1.0
//-----------------------------------------------------------------------------


//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include "stc12c2052.h"
#include "main.h"
#include "fram.h"


//-----------------------------------------------------------------------------
//Global variables
//-----------------------------------------------------------------------------
volatile unsigned char tx_buffer[8];
volatile unsigned char rx_buffer[4]; 
volatile unsigned char tmp_buffer[4];
volatile unsigned char system_status;
volatile bit tx_flag;
volatile bit save_flag;	
volatile bit new_flag;
volatile unsigned char system_clock;
volatile unsigned char uart_time;

		 			   		


/*------------------------------------------------------------------------------
    Function Name   :   main
    Description     :   the main function of the project 
    Parameters  	:   
        Input       :   none
        Output      :   none                        
    Return          :   none
    Notes           :    
------------------------------------------------------------------------------*/
main()
{
	
	/*Init timer and uart*/
	SCON = 0x50;
	TMOD |= 0x21;
	TH1 = 0xFD;	   //9600 bps @11.0592MHz
	TL1 = 0xFD;
	TH0 = 0x4C;	   //0.05 second @11.0592MHz
	TL0 = 0x00;
	

	/*Init SPI*/
	SPCTL = 0xD0;
	SPSTAT = 0xC0;
	delay();

	/*Init variables*/
	system_status = 0;
	tx_flag = 0;
	save_flag = 0;
	new_flag = 0;
	system_clock = 0;
	uart_time = 0;		 			   		


	
	/*read fram data to tx buffer*/
	fram_read_data();
	tx_buffer[0] = 0xff;
	tx_buffer[1] = 0x20;
	tx_buffer[7] = 0xff;


    Enable_Watchdog();

	/*start timer and enable interrupts*/ 
	EA = 1;
	ES = 1;
	ET0 = 1;
	TI = 0;
	RI = 0;	
	TR0 = 1;
	TR1 = 1;
	


	/*main loop*/
	while(1){
		
		if(tx_flag){
			uart_send_data();
			tx_flag = 0;
		}	 			   		

	
		if(save_flag){
			fram_write_data();
			save_flag = 0;
 		}

		Feed_Watchdog();
			
	}//end of while

}



/*------------------------------------------------------------------------------
    Function Name   :   Timer0_ISR
    Description     :   interrupt handler of Timer0 
    Parameters  	:   
        Input       :   none
        Output      :   none                        
    Return          :   none
    Notes           :    
------------------------------------------------------------------------------*/
void Timer0_ISR(void) interrupt 1
{
 
	if(!tx_flag){
		system_clock ++;
		if(system_clock >= 20){
			tx_flag = 1;
			system_clock = 0;
			LED = ~LED;
		}
	}

	//uart packet timeout, return to status 0
	uart_time ++;
	if(uart_time >= 5){
		  uart_time = 0;
		  system_status = 0;
	}

	/* reload value */
	TH0 = 0x4C;
	TL0 = 0x00;

}




/*------------------------------------------------------------------------------
    Function Name   :   Uart_ISR
    Description     :   interrupt handler of Uart 
    Parameters  	:   
        Input       :   none
        Output      :   none                        
    Return          :   none
    Notes           :    
------------------------------------------------------------------------------*/
void Uart_ISR(void) interrupt 4
{
	unsigned char tmp;
	if(RI){
		tmp = SBUF;
		RI = 0;
		uart_time = 0;
		switch(system_status){
		
		case 0:
			if(tmp == 0xff){
				system_status = 1;
			}
			break;

		case 1:
			if(tmp == 0x20){
				system_status = 2;
			}
			else if(tmp == 0xff){
				system_status = 1;
			}
			else{
				system_status = 0;
			}
			break;

		case 2:
			rx_buffer[0] = tmp;
			system_status = 3;
			break;

		case 3:
			rx_buffer[1] = tmp;
			system_status = 4;
			break;

		case 4:
			rx_buffer[2] = tmp;
			system_status = 5;
			break;

		case 5:
			rx_buffer[3] = tmp;
			system_status = 6;
			break;

		case 6:
			if(((rx_buffer[3] + rx_buffer[2] + rx_buffer[1] + rx_buffer[0]) & 0xff) == tmp){			
					system_status = 7;					
			
			}else if(tmp == 0xff){
				system_status = 1;
			
			}else{
				system_status = 0;
			}
			break;

		case 7:
			if(0xff == tmp){
				if((rx_buffer[0] != tx_buffer[2]) || (rx_buffer[1] != tx_buffer[3]) || (rx_buffer[2] != tx_buffer[4]) || (rx_buffer[3] != tx_buffer[5])){ 	
					//Save to tmp buffer for writing to fram
					tmp_buffer[0] = rx_buffer[0];
					tmp_buffer[1] = rx_buffer[1];
					tmp_buffer[2] = rx_buffer[2];
					tmp_buffer[3] = rx_buffer[3];
					
					new_flag = 1;
					save_flag = 1;
				} 
			}
			system_status = 0;
			break;

		default:
			break;		
		
		}//end of "switch"

	}//end of "if RI "

}



/*------------------------------------------------------------------------------
    Function Name   :   uart_send_data
    Description     :   Send 7 bytes to host from uart  
    Parameters  	:   
        Input       :   none
        Output      :   none                        
    Return          :   none
    Notes           :    
------------------------------------------------------------------------------*/  
void uart_send_data(void)
{
	unsigned char i; 

	//change tx data buffer
	if(new_flag){
		tx_buffer[2] = tmp_buffer[0];
		tx_buffer[3] = tmp_buffer[1];
		tx_buffer[4] = tmp_buffer[2];
		tx_buffer[5] = tmp_buffer[3];
		tx_buffer[6] = ((tmp_buffer[3] + tmp_buffer[2] + tmp_buffer[1] + tmp_buffer[0]) & 0xff);
		new_flag = 0;
	}


	for(i=0; i<8; i++){
		SBUF = tx_buffer[i];
		while (!TI);
  		TI = 0;
		delay();		
	}

	


}