61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/**
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* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <stdio.h>
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#include "pico/stdlib.h"
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#include "pico/multicore.h"
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#include "hardware/pio.h"
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#include "hardware/uart.h"
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#include "uart_rx.pio.h"
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// This program
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// - Uses UART1 (the spare UART, by default) to transmit some text
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// - Uses a PIO state machine to receive that text
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// - Prints out the received text to the default console (UART0)
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// This might require some reconfiguration on boards where UART1 is the
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// default UART.
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#define SERIAL_BAUD PICO_DEFAULT_UART_BAUD_RATE
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#define HARD_UART_INST uart1
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// You'll need a wire from GPIO4 -> GPIO3
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#define HARD_UART_TX_PIN 4
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#define PIO_RX_PIN 3
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// Ask core 1 to print a string, to make things easier on core 0
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void core1_main() {
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const char *s = (const char *) multicore_fifo_pop_blocking();
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uart_puts(HARD_UART_INST, s);
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}
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int main() {
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// Console output (also a UART, yes it's confusing)
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setup_default_uart();
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printf("Starting PIO UART RX example\n");
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// Set up the hard UART we're going to use to print characters
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uart_init(HARD_UART_INST, SERIAL_BAUD);
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gpio_set_function(HARD_UART_TX_PIN, GPIO_FUNC_UART);
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// Set up the state machine we're going to use to receive them.
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PIO pio = pio0;
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uint sm = 0;
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uint offset = pio_add_program(pio, &uart_rx_program);
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uart_rx_program_init(pio, sm, offset, PIO_RX_PIN, SERIAL_BAUD);
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// Tell core 1 to print some text to uart1 as fast as it can
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multicore_launch_core1(core1_main);
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const char *text = "Hello, world from PIO! (Plus 2 UARTs and 2 cores, for complex reasons)\n";
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multicore_fifo_push_blocking((uint32_t) text);
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// Echo characters received from PIO to the console
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while (true) {
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char c = uart_rx_program_getc(pio, sm);
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putchar(c);
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}
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}
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