Main.c:
[syntax=c]#include <avr/io.h>
#include "soft_uart.h"
int main(void)
{
UART_init();
while (1)
{
UART_transmit(UART_receive());
}
}[/syntax]
soft_uart.h:
[syntax=c]#ifndef SOFT_UART_H_
#define SOFT_UART_H_
#define TxD_PORT PORTB
#define TxD_PIN PINB
#define TxD_DDR DDRB
#define TxD PB0
#define RxD_PORT PORTB
#define RxD_PIN PINB
#define RxD_DDR DDRB
#define RxD PB1
#define USE_TxD 1
#define USE_RxD 1
#define STOP_BITS 1
#define b_value 252//14.746MHz 9600bps
#ifndef __ASSEMBLER__
void UART_init(void);
void UART_transmit(uint8_t data);
uint8_t UART_receive(void);
#endif
#endif /* SOFT_UART_H_ */[/syntax]
soft_uart.c:
[syntax=c]#include <avr/io.h>
#include "soft_uart.h"
void UART_init(void)
{
#if USE_TxD == 1
TxD_DDR |= (1<<TxD);
#endif
#if USE_RxD == 1
RxD_DDR &= ~(1<<RxD);
RxD_PORT |= (1<<RxD);
#endif
}[/syntax]
soft_uart_asm.S:
[syntax=asm]#include <avr/io.h>
#include "soft_uart.h"
.section .text
UART_delay:
ldi r18, b_value
UART_delay1:
dec r18
brne UART_delay1
ret
.global UART_transmit
UART_transmit:
push r16
push r17
push r18
mov r16, r24
ldi r17, 1+8+STOP_BITS
com r16
sec
transmit1:
brcs transmit2
sbi _SFR_IO_ADDR(TxD_PORT), TxD
rjmp transmit3
transmit2:
cbi _SFR_IO_ADDR(TxD_PORT), TxD
transmit3:
rcall UART_delay
rcall UART_delay
lsr r16
dec r17
brne transmit1
pop r18
pop r17
pop r16
ret
.global UART_receive
UART_receive:
push r16
push r17
push r18
ldi r17, 8+STOP_BITS
receive1:
sbic _SFR_IO_ADDR(RxD_PIN), RxD
rjmp receive1
rcall UART_delay
receive2:
rcall UART_delay
rcall UART_delay
clc
sbic _SFR_IO_ADDR(RxD_PIN), RxD
sec
dec r17
brne receive3
mov r24, r16
pop r18
pop r17
pop r16
ret
receive3:
ror r16
rjmp receive2
.end[/syntax]Statystyki: Napisane przez Patrix354 — 10 lip 2017, o 15:16
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