Data loss SPI communication (Master Slave) (ESP32)

[Nicrus86]

On ESP32, in Arduino framework with include ESP32DMASPIMaster.h and ESP32DMASPISlave.h (https://github.com/hideakitai/ESP32DMASPI), I tried an simple transmition from Master to Slave using a DMA buffer, but there are data lost in reception, regardless of the size of the data sent and the frequency of sending.

=== CODE MASTER SPI ==========

#include <ESP32DMASPIMaster.h>

ESP32DMASPI::Master master;

static const uint32_t BUFFER_SIZE = 12;
uint8_t* spi_master_tx_buf;
uint8_t* spi_master_rx_buf;
uint8_t num_msg = 0;

void set_buffer() {
    for (uint32_t i = 0; i < BUFFER_SIZE; i++) {
        spi_master_tx_buf[i] = i & 0xFF;
    }
    memset(spi_master_rx_buf, 0, BUFFER_SIZE);
}
void set_buffer_new(uint8_t num_msg) {
    for (uint32_t i = 0; i < BUFFER_SIZE; i++) {
        spi_master_tx_buf[i] = num_msg & 0xFF;
    }
    memset(spi_master_rx_buf, 0, BUFFER_SIZE);
} 

void setup() {

    // to use DMA buffer, use these methods to allocate buffer
    spi_master_tx_buf = master.allocDMABuffer(BUFFER_SIZE);
    spi_master_rx_buf = master.allocDMABuffer(BUFFER_SIZE);

    set_buffer();
    delay(5000);

    master.setDataMode(SPI_MODE0);           // default: SPI_MODE0
    master.setFrequency(4000000);            // default: 8MHz (too fast for bread board...)
    master.setMaxTransferSize(BUFFER_SIZE);  // default: 4092 bytes

    // begin() after setting
    master.begin();  // default: HSPI (CS: 15, CLK: 14, MOSI: 13, MISO: 12)
}

void loop() {
    // start and wait to complete transaction
    set_buffer_new(num_msg);

    master.transfer(spi_master_tx_buf, spi_master_rx_buf, BUFFER_SIZE);

    printf(" ====> Buffer TX: ");
    for (size_t i = 0; i < BUFFER_SIZE; ++i) {
        printf("%d ", spi_master_tx_buf[i]);
    }
    printf("\n");
    // show received data (if needed)
    printf("<== Buffer RX: ");
    for (size_t i = 0; i < BUFFER_SIZE; ++i) {
        printf("%d ", spi_master_rx_buf[i]);
    }
    printf("\n");
    num_msg++;
    delay(2000);
}

=== CODE SLAVE SPI ==========

#include <ESP32DMASPISlave.h>

ESP32DMASPI::Slave slave;

static const uint32_t BUFFER_SIZE = 12;
uint8_t* spi_slave_tx_buf;
uint8_t* spi_slave_rx_buf;

void setup() {

    // to use DMA buffer, use these methods to allocate buffer
    spi_slave_tx_buf = slave.allocDMABuffer(BUFFER_SIZE);
    spi_slave_rx_buf = slave.allocDMABuffer(BUFFER_SIZE);

    // set buffer data...

    // slave device configuration
    slave.setDataMode(SPI_MODE0);
    slave.setMaxTransferSize(BUFFER_SIZE);

    // begin() after setting
    slave.begin();  // HSPI = CS: 15, CLK: 14, MOSI: 13, MISO: 12 -> default
                    // VSPI (CS:  5, CLK: 18, MOSI: 23, MISO: 19)
}

void loop() {
    // if there is no transaction in queue, add transaction
    if (slave.remained() == 0) {
        slave.queue(spi_slave_rx_buf, spi_slave_tx_buf, BUFFER_SIZE);
    }

    // if transaction has completed from master,
    // available() returns size of results of transaction,
    // and buffer is automatically updated

    while (slave.available()) {
      for (size_t i = 0; i < BUFFER_SIZE; ++i) {
        printf("%d ", spi_slave_rx_buf[i]);
        spi_slave_rx_buf[i] = 0;
      }
      printf("\n");
      // do something with received data: spi_slave_rx_buf

      slave.pop();
    }
}

[OUTPUT MASTER]

 ====> Buffer TX: 0 0 0 0 0 0 0 0 0 0 0 0 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 1 1 1 1 1 1 1 1 1 1 1 1 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 2 2 2 2 2 2 2 2 2 2 2 2 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 3 3 3 3 3 3 3 3 3 3 3 3 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 4 4 4 4 4 4 4 4 4 4 4 4 
<== Buffer RX: 125 214 149 0 0 0 0 0 0 0 0 0
 ====> Buffer TX: 5 5 5 5 5 5 5 5 5 5 5 5 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 6 6 6 6 6 6 6 6 6 6 6 6 
<== Buffer RX: 125 74 152 0 0 0 0 0 0 0 0 0
 ====> Buffer TX: 7 7 7 7 7 7 7 7 7 7 7 7 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 8 8 8 8 8 8 8 8 8 8 8 8 
<== Buffer RX: 126 180 0 0 0 0 0 0 0 0 0 0
 ====> Buffer TX: 9 9 9 9 9 9 9 9 9 9 9 9 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71
 ====> Buffer TX: 10 10 10 10 10 10 10 10 10 10 10 10 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71 
 ====> Buffer TX: 11 11 11 11 11 11 11 11 11 11 11 11 
<== Buffer RX: 126 164 0 0 0 0 0 0 0 0 0 0 
 ====> Buffer TX: 12 12 12 12 12 12 12 12 12 12 12 12 
<== Buffer RX: 125 214 165 77 91 190 253 103 40 103 146 71

---

In Master Code, I send a data with incremental integer on TX buffer dma. When the Master receive on RX buffer dma some '0', the Slave don't receive the current data on RX buffer dma.

[OUTPUT SLAVE]

0 0 0 0 0 0 0 0 0 0 0 0 
1 1 1 1 1 1 1 1 1 1 1 1 
2 2 2 2 2 2 2 2 2 2 2 2 
3 3 3 3 3 3 3 3 3 3 3 3 
0 0 0 0 0 0 0 0 0 0 0 0 
5 5 5 5 5 5 5 5 5 5 5 5 
0 0 0 0 0 0 0 0 0 0 0 0 
7 7 7 7 7 7 7 7 7 7 7 7 
0 0 0 0 0 0 0 0 0 0 0 0 
9 9 9 9 9 9 9 9 9 9 9 9 
10 10 10 10 10 10 10 10 10 10 10 10 
0 0 0 0 0 0 0 0 0 0 0 0 
12 12 12 12 12 12 12 12 12 12 12 12 
0 0 0 0 0 0 0 0 0 0 0 0 

---

In Slave code, I reset RX buffer dma (with '0') after print current data.

[hideakitai]

Have you tried master/slave examples first? Please try it with a smaller buffer size. If you don't need more than 64 bytes, use the default SPI library and ESP32SPISlave.

[hideakitai]

If you still need help with the problem, please feel free to reopen this issue.