/** * Copyright (c) 2020 Raspberry Pi (Trading) Ltd. * * SPDX-License-Identifier: BSD-3-Clause */ #include "pico/stdlib.h" #include "hardware/uart.h" #include "hardware/irq.h" /// \tag::uart_advanced[] #define UART_ID uart0 #define BAUD_RATE 115200 #define DATA_BITS 8 #define STOP_BITS 1 #define PARITY UART_PARITY_NONE // We are using pins 0 and 1, but see the GPIO function select table in the // datasheet for information on which other pins can be used. #define UART_TX_PIN 0 #define UART_RX_PIN 1 static int chars_rxed = 0; // RX interrupt handler void on_uart_rx() { while (uart_is_readable(UART_ID)) { uint8_t ch = uart_getc(UART_ID); // Can we send it back? if (uart_is_writable(UART_ID)) { // Change it slightly first! ch++; uart_putc(UART_ID, ch); } chars_rxed++; } } int main() { // Set up our UART with a basic baud rate. uart_init(UART_ID, 2400); // Set the TX and RX pins by using the function select on the GPIO // Set datasheet for more information on function select gpio_set_function(UART_TX_PIN, UART_FUNCSEL_NUM(UART_ID, UART_TX_PIN)); gpio_set_function(UART_RX_PIN, UART_FUNCSEL_NUM(UART_ID, UART_RX_PIN)); // Actually, we want a different speed // The call will return the actual baud rate selected, which will be as close as // possible to that requested int __unused actual = uart_set_baudrate(UART_ID, BAUD_RATE); // Set UART flow control CTS/RTS, we don't want these, so turn them off uart_set_hw_flow(UART_ID, false, false); // Set our data format uart_set_format(UART_ID, DATA_BITS, STOP_BITS, PARITY); // Turn off FIFO's - we want to do this character by character uart_set_fifo_enabled(UART_ID, false); // Set up a RX interrupt // We need to set up the handler first // Select correct interrupt for the UART we are using int UART_IRQ = UART_ID == uart0 ? UART0_IRQ : UART1_IRQ; // And set up and enable the interrupt handlers irq_set_exclusive_handler(UART_IRQ, on_uart_rx); irq_set_enabled(UART_IRQ, true); // Now enable the UART to send interrupts - RX only uart_set_irq_enables(UART_ID, true, false); // OK, all set up. // Lets send a basic string out, and then run a loop and wait for RX interrupts // The handler will count them, but also reflect the incoming data back with a slight change! uart_puts(UART_ID, "\nHello, uart interrupts\n"); while (1) tight_loop_contents(); } /// \end:uart_advanced[]

This firmware image was imported from the pico-examples repository. 


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