AVR Serial.c: Rozdiel medzi revíziami
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Bez shrnutí editace |
Bez shrnutí editace |
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Riadok 83: | Riadok 83: | ||
while( !(UART_STATUS_REG & (1 << RECEIVE_COMPLETE_BIT)) ); // wait for data | while( !(UART_STATUS_REG & (1 << RECEIVE_COMPLETE_BIT)) ); // wait for data | ||
return UART_DATA_REG; | return UART_DATA_REG; | ||
} | |||
</source> | |||
'''main.c''' | |||
<source lang="c"> | |||
#include <avr\io.h> | |||
#include "serial.h" // Nasa kniznica... | |||
int main(void) | |||
{ | |||
char c; | |||
initbootuart(); | |||
sendchar('O'); | |||
sendchar('K'); | |||
sendchar('\n'); | |||
for (c=32;c<=127;c++) | |||
sendchar(c); | |||
for (;;) { | |||
/* Do nothing */ | |||
} | |||
} | } | ||
</source> | </source> |
Verzia z 22:28, 30. november 2008
serial.h
/* ************************************************************************* */
/* */
/* Description : Header file for serial.c */
/* Based on AppNote AVR109 - Self-programming */
/* */
/* FileName : serial.h */
/* Compiler : AVR-GCC/avr-libc(>= 1.2.5), TODO: IAR C 3.10C */
/* Revision : 1.7 */
/* Date : 30. November 2008 */
/* Updated by : Richard Balogh */
/* Target platform : ATmega88, TODO: All AVRs with bootloader support */
/* */
/* ************************************************************************* */
void initbootuart( void );
void sendchar( unsigned char );
unsigned char recchar( void );
serial.c
/* ************************************************************************* */
/* */
/* Description : UART communication routines */
/* Based on AppNote AVR109 - Self-programming */
/* */
/* FileName : serial.h */
/* Compiler : AVR-GCC/avr-libc(>= 1.2.5), TODO: IAR C 3.10C */
/* Revision : 1.7 */
/* Date : 30. November 2008 */
/* Updated by : Richard Balogh */
/* Target platform : ATmega88, TODO: All AVRs with bootloader support */
/* */
/* ************************************************************************* */
#include <avr\io.h>
/* baud rate register value calculation */
#define CPU_FREQ 18432000UL // If CKDIV8 checked, then /8!
#define BAUD_RATE 9600
// BAUD = f / 16 * (UBR+1) alebo UBR = CPUFREQ/16/BAUD_RATE-1
#define BRREG_VALUE 119 // hodnota z tabulky v datashhete pre 18,4320MHz, 2x=0, 9600Baud, error = 0%
/* definitions for UART control */ // upravene pre ATmega88
#define BAUD_RATE_LOW_REG UBRR0L // ??? (Staci Low Byte, < 255 )
#define UART_CONTROL_REG_B UCSR0B // OK, checked
#define ENABLE_TRANSMITTER_BIT TXEN0 // OK, checked
#define ENABLE_RECEIVER_BIT RXEN0 // OK, checked
#define UART_STATUS_REG UCSR0A // OK, checked (but also control reg.)
#define DATA_REGISTER_EMPTY_BIT UDRE0 // Added, for possible speed-up
#define TRANSMIT_COMPLETE_BIT TXC0 // OK, checked
#define RECEIVE_COMPLETE_BIT RXC0 // OK, checked
#define UART_CONTROL_REG_C UCSR0C // Added for mode setting
#define UART_DATA_REG UDR0 // OK, checked
void initbootuart(void)
{
BAUD_RATE_LOW_REG = BRREG_VALUE; // OK, preddelic pre 9600
// bit 2x = 0
UART_CONTROL_REG_C = (1<<UCSZ01)|(1<<UCSZ00); // Added: Async. UART, None
// Parity, 8-data, 1 stopbit
UART_CONTROL_REG_B = (1 << ENABLE_RECEIVER_BIT)|
(1 << ENABLE_TRANSMITTER_BIT); // enable receive + transmit
}
void sendchar(unsigned char c)
{
UART_DATA_REG = c; // prepare transmission
while (!(UART_STATUS_REG & (1 << TRANSMIT_COMPLETE_BIT)));// wait until byte sendt
UART_STATUS_REG |= (1 << TRANSMIT_COMPLETE_BIT); // delete TXCflag
}
unsigned char recchar(void)
{
while( !(UART_STATUS_REG & (1 << RECEIVE_COMPLETE_BIT)) ); // wait for data
return UART_DATA_REG;
}
main.c
#include <avr\io.h>
#include "serial.h" // Nasa kniznica...
int main(void)
{
char c;
initbootuart();
sendchar('O');
sendchar('K');
sendchar('\n');
for (c=32;c<=127;c++)
sendchar(c);
for (;;) {
/* Do nothing */
}
}