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100 lines
1.9 KiB
100 lines
1.9 KiB
#pragma once
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//
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// Utilities for UART communication.
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//
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// First, init uart with usart_init().
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// Then enable interrupts you want with usart_XXX_isr_enable().
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//
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#include <avr/io.h>
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#include <avr/pgmspace.h>
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#include <util/delay.h>
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#include <stdbool.h>
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#include <stdint.h>
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/* USART BAUD RATE REGISTER values at 16 MHz */
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enum {
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BAUD_9600 = 103,
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BAUD_14400 = 68,
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BAUD_19200 = 51,
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BAUD_28800 = 34,
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BAUD_38400 = 25,
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BAUD_57600 = 16,
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BAUD_76800 = 12,
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BAUD_115200 = 8,
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BAUD_250k = 3,
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BAUD_500k = 1,
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BAUD_1M = 0,
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};
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/** Init UART with a UBRR value */
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void usart_init(uint16_t ubrr);
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/** Check if there's a byte in the RX register */
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#define usart_rx_ready() (0 != (UCSR0A & (1 << RXC0)))
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/** Check if transmission of everything is done */
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#define usart_tx_ready() (0 != (UCSR0A & (1 << UDRE0)))
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// ---- Enable UART interrupts ------------
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/** Enable or disable RX ISR */
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inline void usart_rx_isr_enable(bool yes)
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{
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set_bit(UCSR0B, RXCIE0, yes);
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}
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/** Enable or disable TX ISR (1 byte is sent) */
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inline void usart_tx_isr_enable(bool yes)
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{
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set_bit(UCSR0B, TXCIE0, yes);
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}
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/** Enable or disable DRE ISR (all is sent) */
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inline void usart_dre_isr_enable(bool yes)
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{
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set_bit(UCSR0B, UDRIE0, yes);
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}
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// ---- Basic IO --------------------------
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/** Send byte over USART */
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inline void usart_tx(uint8_t data)
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{
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// Wait for transmit buffer
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while (!usart_tx_ready());
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// send it
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UDR0 = data;
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}
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/** Receive one byte over USART */
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inline uint8_t usart_rx(void)
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{
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// Wait for data to be received
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while (!usart_rx_ready());
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// Get and return received data from buffer
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return UDR0;
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}
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/** Send byte over UART */
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#define usart_putc(data) usart_tx((data))
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/** Clear receive buffer */
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void usart_clear_rx();
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// ---- Strings ---------------------------
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/** Send string over UART */
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void usart_puts(const char* str);
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/** Send progmem string over UART */
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void usart_puts_P(const char* str);
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