diff --git a/README.md b/README.md index b0cc09de3..f8843910c 100644 --- a/README.md +++ b/README.md @@ -305,6 +305,7 @@ App|Description [uart_tx](pio/uart_tx) | Implement the transmit component of a UART serial port, and print hello world. [ws2812](pio/ws2812) | Examples of driving WS2812 addressable RGB LEDs. [addition](pio/addition) | Add two integers together using PIO. Only around 8 billion times slower than Cortex-M0+. +[uart_pio_dma](pio/uart_pio_dma) | Send and receive data from a UART implemented using the PIO and DMA ### PWM diff --git a/pio/CMakeLists.txt b/pio/CMakeLists.txt index cb1570a81..7b33a38a1 100644 --- a/pio/CMakeLists.txt +++ b/pio/CMakeLists.txt @@ -20,6 +20,7 @@ if (TARGET hardware_pio) add_subdirectory_exclude_platforms(uart_rx) add_subdirectory_exclude_platforms(uart_tx) add_subdirectory_exclude_platforms(ws2812) + add_subdirectory_exclude_platforms(uart_pio_dma) else() message("Skipping PIO examples as hardware_pio is unavailable on this platform") endif() diff --git a/pio/uart_pio_dma/CMakeLists.txt b/pio/uart_pio_dma/CMakeLists.txt new file mode 100644 index 000000000..108477610 --- /dev/null +++ b/pio/uart_pio_dma/CMakeLists.txt @@ -0,0 +1,11 @@ +add_executable(uart_pio_dma) +pico_generate_pio_header(uart_pio_dma ${CMAKE_CURRENT_LIST_DIR}/../uart_rx/uart_rx.pio) +pico_generate_pio_header(uart_pio_dma ${CMAKE_CURRENT_LIST_DIR}/../uart_tx/uart_tx.pio) +target_sources(uart_pio_dma PRIVATE uart_pio_dma.c) +target_link_libraries(uart_pio_dma PRIVATE + pico_stdlib + hardware_pio + hardware_dma + ) +pico_add_extra_outputs(uart_pio_dma) +example_auto_set_url(uart_pio_dma) diff --git a/pio/uart_pio_dma/uart_pio_dma.c b/pio/uart_pio_dma/uart_pio_dma.c new file mode 100644 index 000000000..a9528e234 --- /dev/null +++ b/pio/uart_pio_dma/uart_pio_dma.c @@ -0,0 +1,274 @@ +/** + * Copyright (c) 2024 Raspberry Pi (Trading) Ltd. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include +#include + +#include "pico/stdlib.h" +#include "hardware/pio.h" +#include "hardware/uart.h" +#include "hardware/dma.h" +#include "uart_rx.pio.h" +#include "uart_tx.pio.h" + +// ------- USER CONFIGURATION ----- + +// Send data via GPIO 4 and receives it on GPIO 5 +// *** You must conect these pins with a wire *** +#define GPIO_TX 4 +#define GPIO_RX 5 + +// Use PIO instead of real UART for receiving data +#define USE_PIO_FOR_RX 1 + +// Use DMA rather than polling when receiving data +#define USE_DMA_FOR_RX 1 + +// Use PIO instead of real UART for sending data +#define USE_PIO_FOR_TX 1 + +// Use DMA rather than polling when sending data +#define USE_DMA_FOR_TX 1 + +#define SERIAL_BAUD 921600 +#define HARD_UART_INST uart1 + +#ifndef DMA_IRQ_PRIORITY +#define DMA_IRQ_PRIORITY PICO_SHARED_IRQ_HANDLER_DEFAULT_ORDER_PRIORITY +#endif + +#ifndef PIO_IRQ_PRIORITY +#define PIO_IRQ_PRIORITY PICO_SHARED_IRQ_HANDLER_DEFAULT_ORDER_PRIORITY +#endif + +#define PIO_IRQ_TO_USE 0 +#define DMA_IRQ_TO_USE 0 +// -------------------------------- + + +// dma channels +static uint dma_channel_rx; +static uint dma_channel_tx; + +// pio hardware +#if USE_PIO_FOR_RX +static PIO pio_hw_rx; +static uint pio_sm_rx; +static uint offset_rx; +#endif + +#if USE_PIO_FOR_TX +static PIO pio_hw_tx; +static uint pio_sm_tx; +static uint offset_tx; +#endif + +// read request size for progress +static uint32_t read_size; + +// PIO interrupt handler, called when the state machine fifo is not empty +// note: shouldn't printf in an irq normally! +static void pio_irq_handler() { + dma_channel_hw_t *dma_chan = dma_channel_hw_addr(dma_channel_rx); + printf("pio_rx dma_rx=%u/%u\n", read_size - dma_chan->transfer_count, read_size); +} + +// DMA interrupt handler, called when a DMA channel has transmitted its data +static void dma_irq_handler() { + if (dma_channel_tx >= 0 && dma_irqn_get_channel_status(DMA_IRQ_TO_USE, dma_channel_tx)) { + dma_irqn_acknowledge_channel(DMA_IRQ_TO_USE, dma_channel_tx); + printf("dma_tx done\n"); + } + if (dma_channel_rx >= 0 && dma_irqn_get_channel_status(DMA_IRQ_TO_USE, dma_channel_rx)) { + dma_irqn_acknowledge_channel(DMA_IRQ_TO_USE, dma_channel_rx); + printf("dma_rx done\n"); + } +} + +static void dump_bytes(const char *bptr, uint32_t len) { + unsigned int i = 0; + for (i = 0; i < len;) { + if ((i & 0x0f) == 0) { + printf("\n"); + } else if ((i & 0x07) == 0) { + printf(" "); + } + printf("%02x ", bptr[i++]); + } + printf("\n"); +} + +int main() +{ + setup_default_uart(); + + // setup text we are going to send and what we expect to get back + const char buffer_tx[] = "the quick brown fox jumps over the lazy dog"; + + // Buffer for receiving data + char buffer_rx[sizeof(buffer_tx) - 1] = {0}; + +#if !USE_PIO_FOR_RX || !USE_PIO_FOR_TX + uart_init(HARD_UART_INST, SERIAL_BAUD); +#endif + +#if USE_PIO_FOR_RX + // setup pio for rx + if (!pio_claim_free_sm_and_add_program_for_gpio_range(&uart_rx_mini_program, &pio_hw_rx, &pio_sm_rx, &offset_rx, GPIO_RX, 1, true)) { + panic("failed to allocate pio for rx"); + } + uart_rx_mini_program_init(pio_hw_rx, pio_sm_rx, offset_rx, GPIO_RX, SERIAL_BAUD); +#else + // setup the rx gpio for the uart hardware + gpio_set_function(GPIO_RX, GPIO_FUNC_UART); +#endif + +#if USE_PIO_FOR_TX + // setup pio for tx + if (!pio_claim_free_sm_and_add_program_for_gpio_range(&uart_tx_program, &pio_hw_tx, &pio_sm_tx, &offset_tx, GPIO_TX, 1, true)) { + panic("failed to allocate pio for tx"); + } + uart_tx_program_init(pio_hw_tx, pio_sm_tx, offset_tx, GPIO_TX, SERIAL_BAUD); +#else + // setup the tx gpio for the uart hardware + gpio_set_function(GPIO_TX, GPIO_FUNC_UART); +#endif + +#if USE_PIO_FOR_RX && USE_DMA_FOR_RX + // add a shared irq handler to print some status + irq_add_shared_handler(pio_get_irq_num(pio_hw_rx, PIO_IRQ_TO_USE), pio_irq_handler, PIO_IRQ_PRIORITY); + pio_set_irqn_source_enabled(pio_hw_rx, PIO_IRQ_TO_USE, pio_get_rx_fifo_not_empty_interrupt_source(pio_sm_rx), true); + irq_set_enabled(pio_get_irq_num(pio_hw_rx, PIO_IRQ_TO_USE), true); +#endif + +#if USE_DMA_FOR_RX || USE_DMA_FOR_TX + // add a shared dma handler + irq_add_shared_handler(dma_get_irq_num(DMA_IRQ_TO_USE), dma_irq_handler, DMA_IRQ_PRIORITY); + irq_set_enabled(dma_get_irq_num(DMA_IRQ_TO_USE), true); +#endif + +#if USE_DMA_FOR_RX + // Setup dma for read + dma_channel_rx = dma_claim_unused_channel(false); + if (dma_channel_rx < 0) { + panic("No free dma channels"); + } + dma_channel_config config_rx = dma_channel_get_default_config(dma_channel_rx); + channel_config_set_transfer_data_size(&config_rx, DMA_SIZE_8); + channel_config_set_read_increment(&config_rx, false); + channel_config_set_write_increment(&config_rx, true); + read_size = sizeof(buffer_tx) - 1; + // enable irq for rx + dma_irqn_set_channel_enabled(DMA_IRQ_TO_USE, dma_channel_rx, true); +#if USE_PIO_FOR_RX + // setup dma to read from pio fifo + channel_config_set_dreq(&config_rx, pio_get_dreq(pio_hw_rx, pio_sm_rx, false)); + // 8-bit read from the uppermost byte of the FIFO, as data is left-justified so need to add 3. Don't forget the cast! + dma_channel_configure(dma_channel_rx, &config_rx, buffer_rx, (io_rw_8*)&pio_hw_rx->rxf[pio_sm_rx] + 3, read_size, true); // dma started +#else + // setup dma to read from uart hardware + channel_config_set_dreq(&config_rx, uart_get_dreq(HARD_UART_INST, false)); + dma_channel_configure(dma_channel_rx, &config_rx, buffer_rx, &uart_get_hw(HARD_UART_INST)->dr, read_size, true); // dma started +#endif +#endif + +#if USE_DMA_FOR_TX + // setup dma for write + dma_channel_tx = dma_claim_unused_channel(false); + if (dma_channel_tx < 0) { + panic("No free dma channels"); + } + dma_channel_config config_tx = dma_channel_get_default_config(dma_channel_tx); + channel_config_set_transfer_data_size(&config_tx, DMA_SIZE_8); + channel_config_set_read_increment(&config_tx, true); + channel_config_set_write_increment(&config_tx, false); + // enable irq for tx + dma_irqn_set_channel_enabled(DMA_IRQ_TO_USE, dma_channel_tx, true); +#if USE_PIO_FOR_RX + // setup dma to write to pio fifo + channel_config_set_dreq(&config_tx, pio_get_dreq(pio_hw_tx, pio_sm_tx, true)); + dma_channel_configure(dma_channel_tx, &config_tx, &pio_hw_rx->txf[pio_sm_tx], buffer_tx, sizeof(buffer_tx) - 1, true); // dma started +#else + // setup dma to write to uart hardware + channel_config_set_dreq(&config_tx, uart_get_dreq(HARD_UART_INST, true)); + dma_channel_configure(dma_channel_tx, &config_tx, &uart_get_hw(HARD_UART_INST)->dr, buffer_tx, sizeof(buffer_tx) - 1, true); // dma started +#endif +#endif + +#if USE_DMA_FOR_TX + // Just wait for dma tx to finish + dma_channel_wait_for_finish_blocking(dma_channel_tx); +#elif USE_PIO_FOR_TX + // write to the pio fifo + int count_pio_tx = 0; + while(count_pio_tx < sizeof(buffer_tx) - 1) { + uart_tx_program_putc(pio_hw_tx, pio_sm_tx, buffer_tx[count_pio_tx++]); + } +#else + // write to the uart + uart_puts(HARD_UART_INST, buffer_tx); +#endif + +#if USE_DMA_FOR_RX + // Just wait for dma rx to finish + dma_channel_wait_for_finish_blocking(dma_channel_rx); +#elif USE_PIO_FOR_RX + // read from the pio fifo + int count_pio_rx = 0; + while(count_pio_rx < sizeof(buffer_tx) - 1) { + buffer_rx[count_pio_rx++] = uart_rx_program_getc(pio_hw_rx, pio_sm_rx); + } +#else + // read from the uart + int count_uart_rx = 0; + while(count_uart_rx < sizeof(buffer_tx) - 1) { + buffer_rx[count_uart_rx++] = uart_getc(HARD_UART_INST); + } +#endif + + // check the buffer we received + if (memcmp(buffer_rx, buffer_tx, sizeof(buffer_tx) - 1) == 0) { + printf("Test passed\n"); + } else { + printf("buffer_tx: >%s<\n", buffer_tx); + dump_bytes(buffer_tx, sizeof(buffer_tx)); + printf("result: >%s<\n", buffer_rx); + dump_bytes(buffer_rx, sizeof(buffer_rx)); + printf("Test failed\n"); + assert(0); + } + + // cleanup +#if USE_DMA_FOR_TX + dma_irqn_set_channel_enabled(DMA_IRQ_TO_USE, dma_channel_tx, false); + dma_channel_unclaim(dma_channel_tx); +#endif +#if USE_DMA_FOR_RX + dma_irqn_set_channel_enabled(DMA_IRQ_TO_USE, dma_channel_rx, false); + dma_channel_unclaim(dma_channel_rx); +#endif +#if USE_DMA_FOR_RX || USE_DMA_FOR_TX + irq_remove_handler(dma_get_irq_num(DMA_IRQ_TO_USE), dma_irq_handler); + if (!irq_has_shared_handler(dma_get_irq_num(DMA_IRQ_TO_USE))) { + irq_set_enabled(dma_get_irq_num(DMA_IRQ_TO_USE), false); + } +#endif +#if USE_PIO_FOR_RX + pio_set_irqn_source_enabled(pio_hw_rx, PIO_IRQ_TO_USE, pis_sm0_rx_fifo_not_empty + pio_sm_rx, false); + irq_remove_handler(pio_get_irq_num(pio_hw_rx, PIO_IRQ_TO_USE), pio_irq_handler); + if (!irq_has_shared_handler(pio_get_irq_num(pio_hw_rx, PIO_IRQ_TO_USE))) { + irq_set_enabled(pio_get_irq_num(pio_hw_rx, PIO_IRQ_TO_USE), false); + } + pio_remove_program_and_unclaim_sm(&uart_rx_mini_program, pio_hw_rx, pio_sm_rx, offset_rx); +#endif +#if USE_PIO_FOR_TX + pio_remove_program_and_unclaim_sm(&uart_tx_program, pio_hw_tx, pio_sm_tx, offset_tx); +#endif +#if !USE_PIO_FOR_RX || !USE_PIO_FOR_TX + uart_deinit(HARD_UART_INST); +#endif + return 0; +}