/*
*
* doug_at.c
*
* usage: sdcc -mmcs51 doug_at.c
*
* Getting FLIP to work is troublesome.
* 
* To put chip into boot mode, use this sequence.
*
* press reset, PSEN and release reset when PSEN pressed, then turn on USB switch.
* 
rem
rem compile doug_at.c and uses dfu-programmer to program the chip.
rem https://sourceforge.net/projects/dfu-programmer/
rem

sdcc -mmcs51 --std-c99  doug_at.c
pause
# use lsusb to see if in bootmode.
lsusb
#
# You may need to use sudo otherwise you get device not present
#
sudo dfu-programmer at89c5131 get
sudo dfu-programmer at89c5131 erase
sudo dfu-programmer at89c5131 flash doug_at.ihx
sudo dfu-programmer at89c5131 launch
pause

* http://www.futurlec.com/USBDevBoard.shtml
*
* The board will not go into bootmode with a 5V power supply plugged into jack
* Use USB serial Lead to provide 5V 
*  
* at89_UART_doc4346.pdf
*
* remove rs232 chip
* strap 
* . u .
* .   .
* .   .
* .   .
* .   .
* .   .
* .---.
* .---.
*
* .  .  .  .
* R  G  W  B
* 5v Tx Rx 0v

* connect ttl serial lead to header : red, green, white, black
*
*
* My PL2303HX TTL leads do not work with windows 10 but with LINUX
*
* https://github.com/dfu-programmer/dfu-programmer
*
*/
#include <AT89C513xA.h>
#include <stdio.h>

void serial_IT(void) __interrupt 4 
{
	char uart_data;
if (RI == 1) 
{                    /* if reception occur */
  RI = 0;            /* clear reception flag for next reception */
  uart_data = SBUF;  /* Read receive data */
  SBUF = uart_data;  /* Send back same data on uart*/
}
//else TI = 0;        /* if emission occur */
}               /* clear emission flag for next emission*/

static int intFlag;

void int0_IT(void) __interrupt INT_EXT0 
{
  	
  intFlag = 1;
}

/*
putchar is called by printf();
*/
int putchar(int c)
{
	while(!(SCON & 0x02));
	SCON &= ~0x02;
	SBUF = c & 0xff;
	return (c);
}

void main(void)
{
	unsigned long int i = 0;
	short x ; 

//    ES = 1;      /* Enable serial interrupt*/
//    EA = 1;     /* Enable global interrupt */

	// Set up UART - Find the description in the User's manual!		
	// Set up UART for 115200 baud - Find the description in the User's manual!
//    PCON|=128; // Baudrate double
//    SCON = 124; // 8 Bit UART - PC-compatible
//    TH1=250;  // Divisor= -6 (57600/6=9600 Bd.)
//    TMOD=32; // use timer 1 as baudrate generator
//    TCON=64;  
	
//	TR1 = 1;

//	TCON |= 0x40;
//	SCON |= 0x02;				// Tell putchar() the UART is ready to send.

/*	
;*************************************************
;		UART 115200bps
;*************************************************
		ORL	CKCON0,#00000001B	; 6 CLK PERIOD/MACHINE
		ORL	PCON,#11000000B		; ENABLE THE FRAMING BIT ERROR DETECTION, DOUBLE BAUD RATE
								; AND CHECK FE BIT OF SCON SFR
		ORL	BDRCON,#00001110B	; SPD=1,RBCK =1, TBCK =1
		MOV	SCON,#01010000B		; uart in mode 1 (8 bit), REN=1 
		MOV	BRL,#243			; U CAN SEE THIS VALUE FROM PAGE 71 OF DATASHEET
		ORL	BDRCON,#00010000B	; BRR = 1 , START BAUD RATE RUN
*/  
	// this works.
	CKCON0 = 1;
	PCON   = 0xC0;
	BDRCON = 0x0E;
	SCON   = 0X50;
	BRL    = 0xF3; // 243;
	
	BDRCON = BDRCON | 0x10;
  
//	TCON |= 0x40;
	SCON |= 0x02;				// Tell putchar() the UART is ready to send.

    ES = 1;      /* Enable serial interrupt*/
    EA = 1;     /* Enable global interrupt */
	
	P0 = 0;
    x = 0x0 ;  
	
	for(;;)
	{
		// set PORT 0 to count LED. PORT 0 is open drain. 
		if ( intFlag == 1){	
		  x++ ;
		  intFlag = 0;
        }		  
		
		x++;
		P0 = x&0xff; 
		printf("UUU 555   Hello World! x= %04X \n\r",x);
//		for(i = 0; i < 147456; i++); // Sleep
		for(i = 0; i < 14745; i++); // Sleep
	}
}