rossihwang/pico_dma_uart

raspberry pi pico dma uart example

pico_dma_uart's Issues

Continuous UART read data on uart_dreq using DMA on Pico

Hello,
I'm using dma to read data from neo m8n gps module, it sends nmea sentences every 100 ms.
Since it's a lots of data roughly an uint8_t 400 element array.
So, I set up the dma and uart as following but I'm not able to read data more than 64 bytes. Only the ring buffer is creating problems here, if it's set to values more that 6 the the pico along with usb hangs. My keyboard and mouse also don't works or malfunctions😂.

//-----------------------------------------------------------------//
#include <string.h>
#include <pico/time.h>
#include <stdio.h>
#include "pico/stdlib.h"
#include <hardware/dma.h>
#include <hardware/uart.h>

#define gps_buf_max_expctd_len 64
uint32_t gps_raw_buff[gps_buf_max_expctd_len];

static void UART_setup(int baud){
uart_init(uart1, 2400);
gpio_set_function(8, GPIO_FUNC_UART);
gpio_set_function(9, GPIO_FUNC_UART);
int __unused actual = uart_set_baudrate(uart1, baud);
uart_set_hw_flow(uart1, false, false);
uart_set_format(uart1, 8, 1, UART_PARITY_NONE);
uart_set_fifo_enabled(uart1, false);
}

static void configure_dma() {
int chan = 0;//dma_claim_unused_channel(true);
dma_channel_config config = dma_channel_get_default_config(chan);
channel_config_set_transfer_data_size(&config, DMA_SIZE_8);
channel_config_set_read_increment(&config, false);
channel_config_set_write_increment(&config, true);
channel_config_set_ring(&config, true, 6);
channel_config_set_dreq(&config, uart_get_dreq(uart1, false));

dma_channel_configure(
    chan,
    &config,
    gps_raw_buff,
    &uart1_hw->dr,
    UINT32_MAX,
    true
);

}

int main() {

stdio_usb_init();
UART_setup(9600);
sleep_ms(100);
GPS_init();
configure_dma();


while(1){
    sleep_ms(100);


    printf("%.*s\n------------------------------\n", gps_buf_max_expctd_len, gps_raw_buff);
    
}

}

Note: uart and usb both enabled at CMakeLists.txt
Also gps data rate10Hz, and baud115200(including pico uart to 115200) was set using GPS_init();