184 lines
3.4 KiB
C
184 lines
3.4 KiB
C
/*
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* Author: Jake Goodwin
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* Date: 2023
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* Description: Small library to communicate with the AT-09 bluetooth module.
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*/
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <avr/sleep.h>
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#include <util/delay.h>
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#include "avr_usart.h"
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//#############################
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//Globals
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//#############################
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int main() {
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unsigned char* tx_buffer[16];
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unsigned char* rx_buffer[16];
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led_blink();
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led_blink();
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led_blink();
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_delay_ms(1000);
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_delay_ms(1000);
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init_usart0();
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//enable interrupts
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sei();
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uint8_t buf_len = 12;
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unsigned char data[12] = "HELLO WORLD\0";
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while(1) {
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serial0_write(data, buf_len);
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_delay_ms(1000);
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}
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return 0;
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}
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//#############################
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//FUNCTIONS
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//#############################
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/*
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* Input: None
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* Output: None
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* Description: init usart0 hardware in async mode
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*/
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void init_usart0(void) {
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//DDRB |= (1<<TX_DDR)|(0<<RX_DDR);
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//PORTD |= (0<<TX_PIN)|(0<<RX_PIN);
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//setup stuff for usart communications.
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//set baud rate, this is 9600Baud with a 8Mhz clock
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//UBRR0H |= (uint8_t) (BT_UBRR>>8);
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//UBRR0L |= (uint8_t) BT_UBRR;
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UBRR0H |= (uint8_t) (0x33>>8);
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UBRR0L |= (uint8_t) 0x33;
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//Enable recv and Transmit pins, overrides other uses.
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//IN the usart control and status register 0B
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UCSR0B = (1<<RXEN0) | (1<<TXEN0);
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//setting the data frame format
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//We leave the 2MSB zero for async serial. And we also don't enable
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//parity bits for now. We set a 2bit stop bit and 8bit char size.
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UCSR0C = (1<<USBS0) | (3<<UCSZ00);
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}
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/*
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* Input: a 8bit char
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* Output: None
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* Description: Sends a char over usart0
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*/
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void tx_usart0(unsigned char data) {
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//first wait for the transmit buffer to be empty
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while(!(UCSR0A & (1<<UDRE0))) {
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;//Equiv of continue
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}
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//now that it's empty, fill buffer with TX data.
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UDR0 = data;
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}
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/*
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* Input:None
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* Output: a 8bit char
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* Description: Recvs a char over usart0
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*/
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unsigned char rx_usart0(void) {
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//first wait for the data to be received.
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while(!(UCSR0A & (1<<RXC0))) {
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;//Equiv of continue
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}
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//now return the data
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return (unsigned char) UDR0;
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}
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/*
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* Inupt: None
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* Output: None
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* Description: Nothing right now.
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*/
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void serial0_enable_timeouts(uint8_t ms) {
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;
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}
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/*
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* Inupt: None
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* Output: None
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* Description:
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*/
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void serial0_write(char* buffer, uint8_t write_length) {
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for(uint8_t i = 0; i < write_length; i++) {
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tx_usart0(buffer[i]);
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}
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}
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/*
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* Inupt: A serialbuffer and length
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* Output: None
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* Description: Reads the serial data into a buffer of x length.
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*/
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void serial0_read(char* buffer, uint8_t buf_length) {
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for(uint8_t i = 0; i < buf_length; i++) {
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buffer[i] = rx_usart0();
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}
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}
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/*
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* Inupt: BUAD RATE as uint8_t
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* Output: None
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* Description: Sets the baud rate of the serial usart0
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* VALUES @ 1Mhz:
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* 207 --> 300bps
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* 103 --> 600bps
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* 51 --> 1200bps
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* 25 --> 2400bps
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* 12 --> 4800bps
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* 6 --> 9600bps !!! 7% error rate
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*/
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void serial0_set_baud(uint8_t buad) {
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UBRR0H |= (uint8_t) (baud>>8);
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UBRR0L |= (uint8_t) baud;
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}
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/*
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* Input: None
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* Output: None
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* Description: Toggles the pin for the LED indicator.
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*/
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static void led_blink(void) {
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//Set the DDR for output.
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DDRC |= (1<<LED_PIN);
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PORTC ^= (1<<LED_PIN);
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_delay_ms(250);
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PORTC ^= (1<<LED_PIN);
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_delay_ms(250);
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}
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