309 lines
8.9 KiB
C++
309 lines
8.9 KiB
C++
#include <stdio.h>
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#include <string.h>
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#include "pico/stdlib.h"
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#include "pico/unique_id.h"
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#include "hardware/uart.h"
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#include "hardware/irq.h"
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#include "hardware/gpio.h"
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#include "hardware/clocks.h"
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#include "tusb.h"
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//--------------------------------------------------------------------+
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// UART Configuration
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//--------------------------------------------------------------------+
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#define UART_ID uart0
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#define UART_IRQ UART0_IRQ
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#define UART_TX_PIN 0
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#define UART_RX_PIN 1
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#define DEFAULT_BAUD 115200
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// Activity / Heartbeat LED Pin
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#define LED_PIN_WS 16
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#define LED_PIN_PICO 25
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// UART RX Ring Buffer for capture
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#define BUFFER_SIZE 4096
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static volatile struct {
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uint8_t buf[BUFFER_SIZE];
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volatile uint32_t head;
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volatile uint32_t tail;
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} uart_rx_ring;
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static inline bool ring_is_empty(void) {
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return uart_rx_ring.head == uart_rx_ring.tail;
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}
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static inline void ring_push(uint8_t c) {
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uint32_t next = (uart_rx_ring.head + 1) % BUFFER_SIZE;
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if (next != uart_rx_ring.tail) {
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uart_rx_ring.buf[uart_rx_ring.head] = c;
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uart_rx_ring.head = next;
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}
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}
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static inline uint8_t ring_pop(void) {
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uint8_t c = uart_rx_ring.buf[uart_rx_ring.tail];
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uart_rx_ring.tail = (uart_rx_ring.tail + 1) % BUFFER_SIZE;
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return c;
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}
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//--------------------------------------------------------------------+
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// UART Interrupt Handler
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//--------------------------------------------------------------------+
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static void on_uart_rx(void) {
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while (uart_is_readable(UART_ID)) {
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uint8_t ch = (uint8_t)uart_getc(UART_ID);
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ring_push(ch);
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}
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}
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//--------------------------------------------------------------------+
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// Hardware UART Setup
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//--------------------------------------------------------------------+
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static void setup_uart(uint32_t baudrate) {
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uart_init(UART_ID, baudrate);
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gpio_set_function(UART_TX_PIN, GPIO_FUNC_UART);
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gpio_set_function(UART_RX_PIN, GPIO_FUNC_UART);
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gpio_pull_up(UART_RX_PIN);
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uart_set_hw_flow(UART_ID, false, false);
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uart_set_format(UART_ID, 8, 1, UART_PARITY_NONE);
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uart_set_fifo_enabled(UART_ID, true);
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// Set up and enable the interrupt handlers
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irq_set_exclusive_handler(UART_IRQ, on_uart_rx);
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irq_set_enabled(UART_IRQ, true);
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// Enable UART RX interrupt
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uart_set_irq_enables(UART_ID, true, false);
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}
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//--------------------------------------------------------------------+
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// USB Descriptors
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//--------------------------------------------------------------------+
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#define USB_VID 0x2E8A // Raspberry Pi
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#define USB_PID 0x000A // Raspberry Pi Pico CDC
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#define USB_BCD 0x0200
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tusb_desc_device_t const desc_device = {
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.bLength = sizeof(tusb_desc_device_t),
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.bDescriptorType = TUSB_DESC_DEVICE,
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.bcdUSB = USB_BCD,
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.bDeviceClass = TUSB_CLASS_MISC,
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.bDeviceSubClass = MISC_SUBCLASS_COMMON,
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.bDeviceProtocol = MISC_PROTOCOL_IAD,
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.bMaxPacketSize0 = CFG_TUD_ENDPOINT0_SIZE,
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.idVendor = USB_VID,
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.idProduct = USB_PID,
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.bcdDevice = 0x0100,
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.iManufacturer = 0x01,
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.iProduct = 0x02,
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.iSerialNumber = 0x03,
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.bNumConfigurations = 0x01
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};
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extern "C" uint8_t const *tud_descriptor_device_cb(void) {
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return (uint8_t const *) &desc_device;
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}
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enum {
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ITF_NUM_CDC = 0,
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ITF_NUM_CDC_DATA,
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ITF_NUM_TOTAL
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};
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#define EPNUM_CDC_NOTIF 0x81
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#define EPNUM_CDC_OUT 0x02
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#define EPNUM_CDC_IN 0x82
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#define CONFIG_TOTAL_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN)
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uint8_t const desc_configuration[] = {
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TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
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TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),
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};
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extern "C" uint8_t const *tud_descriptor_configuration_cb(uint8_t index) {
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(void) index;
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return desc_configuration;
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}
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enum {
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STRID_LANGID = 0,
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STRID_MANUFACTURER,
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STRID_PRODUCT,
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STRID_SERIAL,
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STRID_CDC_INTERFACE,
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};
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static char const *string_desc_arr[] = {
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(const char[]) { 0x09, 0x04 },
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"Waveshare",
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"RP2350 USB-UART Adapter",
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NULL,
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"RP2350 CDC UART",
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};
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static uint16_t _desc_str[64];
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extern "C" uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
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(void) langid;
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size_t chr_count = 0;
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switch (index) {
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case STRID_LANGID:
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memcpy(&_desc_str[1], string_desc_arr[0], 2);
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chr_count = 1;
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break;
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case STRID_SERIAL: {
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pico_unique_board_id_t id;
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pico_get_unique_board_id(&id);
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char serial_str[2 * PICO_UNIQUE_BOARD_ID_SIZE_BYTES + 1];
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pico_get_unique_board_id_string(serial_str, sizeof(serial_str));
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chr_count = strlen(serial_str);
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if (chr_count > 32) chr_count = 32;
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for (size_t i = 0; i < chr_count; i++) {
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_desc_str[1 + i] = serial_str[i];
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}
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break;
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}
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default: {
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if (!(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0]))) {
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return NULL;
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}
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const char *str = string_desc_arr[index];
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if (!str) return NULL;
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chr_count = strlen(str);
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size_t const max_count = sizeof(_desc_str) / sizeof(_desc_str[0]) - 1;
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if (chr_count > max_count) chr_count = max_count;
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for (size_t i = 0; i < chr_count; i++) {
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_desc_str[1 + i] = str[i];
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}
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break;
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}
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}
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_desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
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return _desc_str;
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}
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//--------------------------------------------------------------------+
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// TinyUSB CDC Callbacks
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//--------------------------------------------------------------------+
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extern "C" void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
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(void) itf;
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(void) dtr;
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(void) rts;
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}
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extern "C" void tud_cdc_line_coding_cb(uint8_t itf, cdc_line_coding_t const* p_line_coding) {
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(void) itf;
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if (p_line_coding->bit_rate > 0) {
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uart_set_baudrate(UART_ID, p_line_coding->bit_rate);
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}
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uint data_bits = (p_line_coding->data_bits >= 5 && p_line_coding->data_bits <= 8)
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? p_line_coding->data_bits : 8;
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uint stop_bits = (p_line_coding->stop_bits == 2) ? 2 : 1;
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uart_parity_t parity = UART_PARITY_NONE;
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if (p_line_coding->parity == 1) {
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parity = UART_PARITY_ODD;
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} else if (p_line_coding->parity == 2) {
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parity = UART_PARITY_EVEN;
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}
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uart_set_format(UART_ID, data_bits, stop_bits, parity);
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}
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//--------------------------------------------------------------------+
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// Main Bridge Task
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//--------------------------------------------------------------------+
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static void cdc_uart_bridge_task(void) {
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// 1. Drain any available hardware UART RX bytes directly into ring buffer
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while (uart_is_readable(UART_ID)) {
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ring_push((uint8_t)uart_getc(UART_ID));
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}
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// 2. Forward UART RX -> USB CDC TX
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if (!ring_is_empty()) {
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uint32_t available = tud_cdc_write_available();
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if (available > 0) {
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uint8_t tx_buf[64];
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uint32_t count = 0;
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while (count < sizeof(tx_buf) && count < available && !ring_is_empty()) {
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tx_buf[count++] = ring_pop();
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}
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if (count > 0) {
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tud_cdc_write(tx_buf, count);
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tud_cdc_write_flush();
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}
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}
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}
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// 3. Forward USB CDC RX -> UART TX
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if (tud_cdc_available()) {
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uint8_t usb_rx_buf[64];
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uint32_t count = tud_cdc_read(usb_rx_buf, sizeof(usb_rx_buf));
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if (count > 0) {
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uart_write_blocking(UART_ID, usb_rx_buf, count);
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}
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}
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}
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//--------------------------------------------------------------------+
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// Main Entry
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//--------------------------------------------------------------------+
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int main(void) {
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stdio_init_all();
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// Initialize Activity LED
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gpio_init(LED_PIN_WS);
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gpio_set_dir(LED_PIN_WS, GPIO_OUT);
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gpio_put(LED_PIN_WS, 0);
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#ifdef LED_PIN_PICO
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gpio_init(LED_PIN_PICO);
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gpio_set_dir(LED_PIN_PICO, GPIO_OUT);
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gpio_put(LED_PIN_PICO, 0);
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#endif
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// Initialize UART0 on GP0 (TX) and GP1 (RX)
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setup_uart(DEFAULT_BAUD);
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// Initialize TinyUSB Device stack
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tusb_init();
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uint32_t last_blink = 0;
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bool led_state = false;
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while (true) {
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// Process TinyUSB device events
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tud_task();
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// Process bidirectional data transfer
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cdc_uart_bridge_task();
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// Heartbeat blink (toggle every 250ms)
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uint32_t now = to_ms_since_boot(get_absolute_time());
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if (now - last_blink >= 250) {
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last_blink = now;
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led_state = !led_state;
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gpio_put(LED_PIN_WS, led_state);
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#ifdef LED_PIN_PICO
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gpio_put(LED_PIN_PICO, led_state);
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#endif
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}
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}
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return 0;
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}
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