Initial Release

src/rp2_common/pico_stdio_uart/CMakeLists.txt

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+add_library(pico_stdio_uart INTERFACE)
+
+target_sources(pico_stdio_uart INTERFACE
+        ${CMAKE_CURRENT_LIST_DIR}/stdio_uart.c
+)
+
+target_include_directories(pico_stdio_uart INTERFACE ${CMAKE_CURRENT_LIST_DIR}/include)
+
+target_compile_definitions(pico_stdio_uart INTERFACE
+        PICO_STDIO_UART=1
+)
+
+target_link_libraries(pico_stdio_uart INTERFACE pico_stdio)

src/rp2_common/pico_stdio_uart/include/pico/stdio_uart.h

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+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef _PICO_STDIO_UART_H
+#define _PICO_STDIO_UART_H
+
+#include "pico/stdio.h"
+#include "hardware/uart.h"
+
+/** \brief Support for stdin/stdout using UART
+ *  \defgroup pico_stdio_uart pico_stdio_uart
+ *  \ingroup pico_stdio
+ *
+ *  Linking this library or calling `pico_enable_stdio_uart(TARGET)` in the CMake (which
+ *  achieves the same thing) will add UART to the drivers used for standard output
+ */
+
+// PICO_CONFIG: PICO_STDIO_UART_DEFAULT_CRLF, Default state of CR/LF translation for UART output, type=bool, default=PICO_STDIO_DEFAULT_CRLF, group=pico_stdio_uart
+#ifndef PICO_STDIO_UART_DEFAULT_CRLF
+#define PICO_STDIO_UART_DEFAULT_CRLF PICO_STDIO_DEFAULT_CRLF
+#endif
+
+extern stdio_driver_t stdio_uart;
+
+/*! \brief Explicitly initialize stdin/stdout over UART and add it to the current set of stdin/stdout drivers
+ *  \ingroup pico_stdio_uart
+ *
+ * This method sets up PICO_DEFAULT_UART_TX_PIN for UART output (if defined), PICO_DEFAULT_UART_RX_PIN for input (if defined)
+ * and configures the baud rate as PICO_DEFAULT_UART_BAUD_RATE.
+ *
+ * \note this method is automatically called by \ref stdio_init_all() if `pico_stdio_uart` is included in the build
+ */
+void stdio_uart_init();
+
+/*! \brief Explicitly initialize stdout only (no stdin) over UART and add it to the current set of stdout drivers
+ *  \ingroup pico_stdio_uart
+ *
+ * This method sets up PICO_DEFAULT_UART_TX_PIN for UART output (if defined) , and configures the baud rate as PICO_DEFAULT_UART_BAUD_RATE
+ */
+void stdout_uart_init();
+
+/*! \brief Explicitly initialize stdin only (no stdout) over UART and add it to the current set of stdin drivers
+ *  \ingroup pico_stdio_uart
+ *
+ * This method sets up PICO_DEFAULT_UART_RX_PIN for UART input (if defined) , and configures the baud rate as PICO_DEFAULT_UART_BAUD_RATE
+ */
+void stdin_uart_init();
+
+/*! \brief Perform custom initialization initialize stdin/stdout over UART and add it to the current set of stdin/stdout drivers
+ *  \ingroup pico_stdio_uart
+ *
+ * \param uart the uart instance to use, \ref uart0 or \ref uart1
+ * \param baud_rate the baud rate in Hz
+ * \param tx_pin the UART pin to use for stdout (or -1 for no stdout)
+ * \param rx_pin the UART pin to use for stdin (or -1 for no stdin)
+ */
+void stdio_uart_init_full(uart_inst_t *uart, uint baud_rate, int tx_pin, int rx_pin);
+
+#endif

src/rp2_common/pico_stdio_uart/stdio_uart.c

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+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "pico/stdio/driver.h"
+#include "pico/stdio_uart.h"
+#include "pico/binary_info.h"
+#include "hardware/gpio.h"
+
+static uart_inst_t *uart_instance;
+
+#if PICO_NO_BI_STDIO_UART
+#define stdio_bi_decl_if_func_used(x)
+#else
+#define stdio_bi_decl_if_func_used bi_decl_if_func_used
+#endif
+
+void stdio_uart_init() {
+    int tx_pin = -1;
+    int rx_pin = -1;
+#if defined(PICO_DEFAULT_UART_TX_PIN) && PICO_DEFAULT_UART_TX_PIN != -1
+    tx_pin = PICO_DEFAULT_UART_TX_PIN;
+#if defined(PICO_DEFAULT_UART_RX_PIN) && PICO_DEFAULT_UART_RX_PIN != -1
+    rx_pin = PICO_DEFAULT_UART_RX_PIN;
+    stdio_bi_decl_if_func_used(bi_program_feature("UART stdin / stdout"));
+    bi_decl_if_func_used(bi_2pins_with_func(PICO_DEFAULT_UART_RX_PIN, PICO_DEFAULT_UART_TX_PIN, GPIO_FUNC_UART));
+#else
+    stdio_bi_decl_if_func_used(bi_program_feature("UART stdout"));
+    bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_TX_PIN, GPIO_FUNC_UART));
+#endif
+#elif defined(PICO_DEFAULT_UART_RX_PIN) && PICO_DEFAULT_UART_RX_PIN != -1
+    rx_pin = PICO_DEFAULT_UART_RX_PIN;
+    stdio_bi_decl_if_func_used(bi_program_feature("UART stdin"));
+    bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_RX_PIN, GPIO_FUNC_UART));
+#endif
+#if !defined(PICO_DEFAULT_UART_BAUD_RATE) || !defined(uart_default)
+    panic("UART baud rate undefined");
+#else
+    stdio_uart_init_full(uart_default, PICO_DEFAULT_UART_BAUD_RATE, tx_pin, rx_pin);
+#endif
+}
+
+void stdout_uart_init() {
+#ifdef PICO_DEFAULT_UART_TX_PIN
+    bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_TX_PIN, GPIO_FUNC_UART));
+#if !defined(PICO_DEFAULT_UART_BAUD_RATE) || !defined(uart_default)
+    panic("UART baud rate undefined");
+#else
+    stdio_bi_decl_if_func_used(bi_program_feature("UART stdout"));
+    stdio_uart_init_full(uart_default, PICO_DEFAULT_UART_BAUD_RATE, PICO_DEFAULT_UART_TX_PIN, -1);
+#endif
+#endif
+}
+
+void stdin_uart_init() {
+#ifdef PICO_DEFAULT_UART_RX_PIN
+    bi_decl_if_func_used(bi_1pin_with_func(PICO_DEFAULT_UART_RX_PIN, GPIO_FUNC_UART));
+#if !defined(PICO_DEFAULT_UART_BAUD_RATE) || !defined(uart_default)
+    panic("UART baud rate undefined");
+#else
+    stdio_bi_decl_if_func_used(bi_program_feature("UART stdin"));
+    stdio_uart_init_full(uart_default, PICO_DEFAULT_UART_BAUD_RATE, -1, PICO_DEFAULT_UART_RX_PIN);
+#endif
+#endif
+}
+
+void stdio_uart_init_full(struct uart_inst *uart, uint baud_rate, int tx_pin, int rx_pin) {
+    uart_instance = uart;
+    uart_init(uart_instance, baud_rate);
+    if (tx_pin != -1) gpio_set_function(tx_pin, GPIO_FUNC_UART);
+    if (rx_pin != -1) gpio_set_function(rx_pin, GPIO_FUNC_UART);
+    stdio_set_driver_enabled(&stdio_uart, true);
+}
+
+static void stdio_uart_out_chars(const char *buf, int length) {
+    for (uint i = 0; i <length; i++) {
+        uart_putc(uart_default, buf[i]);
+    }
+}
+
+int stdio_uart_in_chars(char *buf, int length) {
+    int i=0;
+    while (i<length && uart_is_readable(uart_default)) {
+        buf[i++] = uart_getc(uart_default);
+    }
+    return i ? i : PICO_ERROR_NO_DATA;
+}
+
+stdio_driver_t stdio_uart = {
+    .out_chars = stdio_uart_out_chars,
+    .in_chars = stdio_uart_in_chars,
+#if PICO_STDIO_ENABLE_CRLF_SUPPORT
+    .crlf_enabled = PICO_STDIO_UART_DEFAULT_CRLF
+#endif
+};