mirror of
https://github.com/halleysfifthinc/AVCLAN-Mockingboard.git
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Allen Hill
48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
// Copyright (C) 2026 Allen Hill <allenofthehills@gmail.com>
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// SPDX-License-Identifier: GPL-3.0-or-later
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#include <avr/io.h>
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#include <stdint.h>
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#include <stdio.h>
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#include "hal/stdio.h"
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#include "timing_avr.h" // IWYU pragma: export
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#include "usart.h" // jnk0le AVR-UART-lib
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// Raw stdout backend: emit the byte verbatim, no '\n' -> "\r\n" translation
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// (unlike the lib's uart_putchar). Keeps binary frame payloads intact.
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static int stdio_putchar(char data, FILE *stream) {
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(void)stream;
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uart0_putc(data);
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return 0;
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}
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// Non-blocking stdin backend: next received byte, or _FDEV_EOF when the RX ring
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// is empty (uart0_getData() returns a negative value when there is no data).
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static int stdio_getchar(FILE *stream) {
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(void)stream;
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int16_t c = uart0_getData();
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return c < 0 ? _FDEV_EOF : c;
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}
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// One raw RW stream for the stdio UART: verbatim byte output, non-blocking
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// input.
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static FILE stdio_stream =
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FDEV_SETUP_STREAM(stdio_putchar, stdio_getchar, _FDEV_SETUP_RW);
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void stdio_init(void) {
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// The lib's uart0_init configures the USART registers/baud but not the pins;
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// keep the ATtiny3216 pin-mux the old driver did.
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PORTMUX.CTRLB = PORTMUX_USART0_ALTERNATE_gc; // TxD/RxD on PA1/PA2
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PORTA.DIRSET = PIN1_bm; // TxD output
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PORTA.DIRCLR = PIN2_bm; // RxD input
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#ifdef USE_DOUBLE_SPEED
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uart0_init(DOUBLE_BAUD_CALC(1200000));
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#else
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uart0_init(BAUD_CALC(1200000));
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#endif
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stdout = stdin = &stdio_stream; // printf/fputs/fwrite + non-blocking getchar
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}
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