#define PORTA 5
#define PORTB 6

#pragma RS232_TXPORT 5
#pragma RS232_RXPORT 5
#pragma RS232_TXPIN  2 
#pragma RS232_RXPIN  0  //not really,,,,
#pragma RS232_BAUD 2400
#pragma TRUE_RS232 1


//Timing settings

#define TRUE 1
#define FALSE 0

#pragma  TURBO_MODE TRUE

#pragma CLOCK_FREQ 50000000
//#pragma CLOCK_FREQ  4000000


//port b, all inputs for bits.
//port a0=output, step motor
//port a1=input, data ready
//port a2=output, RS-232.
//port a3=input, switch





#define P_READAVAIL 0
#define P_ADVANCE_TAPE 1
#define P_SWITCH 3
#define P_RS232 2

char thechar;
int valid_data;

void reset_advance(void);
void do_advance(void);
void check_switch(void);
void init (void);
void drop_motor(void);
void my_putchar (char);
void raise_motor(void);










void main( void )
{
init();








check_switch();
drop_motor();
while (TRUE==TRUE)
{


while (input_pin_port_a(P_READAVAIL)==0);
thechar=input_port_b();
raise_motor();
while (input_pin_port_a(P_READAVAIL)==1);
my_putchar(~thechar);
check_switch();
drop_motor();





}

}


void drop_motor(void)
{
 output_low_port_a(P_ADVANCE_TAPE) ;


}

void raise_motor(void)
{
output_high_port_a(P_ADVANCE_TAPE) ;
}

void reset_advance (void)

{

 output_low_port_a(P_ADVANCE_TAPE) ;
 delay_us (10);
 output_high_port_a(P_ADVANCE_TAPE) ;


return;

}

void do_advance(void)
{

 output_low_port_a(P_ADVANCE_TAPE) ;
 delay_us (10);
 //output_high_port_a(P_ADVANCE_TAPE) ;
     

return;
}

void check_switch(void)

{

while ( input_pin_port_a( P_SWITCH )==1 );


return;

}


void init (void)
{

output_port_a(11111111b);


asm mov M,#00001111b   ;the direction
asm mov W,#11111001b
asm mov !RA,W

asm mov W,#$FF
asm mov !RB,W


asm mov M,#$0E   ;the MODE pullup registers
asm mov W, #$00
asm mov !RB,W  ;all B pulled up.
asm mov W, #$00
asm mov !RA,W  ;all A pulled up.

asm mov M,#$0d   ;the MODE pullup registers
asm mov W, #$00
asm mov !RB,W  ;all Schmidt
asm mov W, #$00
asm mov !RA,W  ;all Schmidt


asm mov M,#$0D    ;B is TTL,all others CMOS
asm mov W,#$00
asm mov !RB,W


}


void my_putchar(char x)


{
char ct=0;
char odd_even=0;
output_low_port_a(P_RS232) ;
delay_ms(3);
delay_us(200);
delay_us(100);
while (ct<8)
{


if ((x&00000001b)==TRUE)
{
output_high_port_a(P_RS232);
odd_even++;

}
else

{
output_low_port_a(P_RS232);


}

x=x>>1;
ct++;

delay_ms(3);
delay_us(200);
delay_us(100);


}


if ((odd_even&00000001b)==TRUE)
{
output_high_port_a(P_RS232);


}
else

{
output_low_port_a(P_RS232);


}


delay_ms(3);
delay_us(200);
delay_us(100);




output_high_port_a(P_RS232);
delay_ms(3);
delay_us(200);
delay_us(100);


}  P6ˆ Yˆ  