Question

嗨，我正在尝试读取以下示例中* rx_buffer的值，该值是spi_transaction_t结构的成员。

struct spi_transaction_t {
    [...]
    union {
       void *rx_buffer; //< Pointer to receive buffer, or NULL for no MISO phase. Written by 4 bytes-unit if DMA is used.
    uint8_t rx_data[4]; //< If SPI_USE_RXDATA is set, data is received directly to this variable
    };
};  


//Queue transaction
static void send_lines(spi_device_handle_t spi)
{
    esp_err_t ret;
    int x;
    [...]
    for (x=0; x<6; x++) {
        ret=spi_device_queue_trans(spi, &trans[x], portMAX_DELAY);
        assert(ret==ESP_OK);
    }

}

//Dequeue transaction
static void send_line_finish(spi_device_handle_t spi)
{
    spi_transaction_t *rtrans;
    esp_err_t ret;
    for (int x=0; x<6; x++) {
        ret=spi_device_get_trans_result(spi, &rtrans, portMAX_DELAY);
        assert(ret==ESP_OK);
    }
}

代码来自以下示例： https://github.com/espressif/esp-idf/blob/221eced06daff783afde6e378f6f84a82867f758/examples/peripherals/spi_master/main/spi_master_example_main.c#L342

我现在正试图从* rx_buffer出队数据并将其写入另一个缓冲区。类似于以下内容，但是我正在努力使用指向指针结构的指针。

//Dequeue transaction
static void send_line_finish(spi_device_handle_t spi)
{
    spi_transaction_t *rtrans;
    esp_err_t ret;
    int16_t data_buffer[6];

    for (int x=0; x<6; x++) {
        ret=spi_device_get_trans_result(spi, &rtrans, portMAX_DELAY);
        assert(ret==ESP_OK);
        data_buffer[x] = (int16_t**)rtrans->rx_buffer;
    }
}

编辑：文档说：

通常，将从以下设备读取要传输到设备的数据：或写入rx_buffer和事务结构的tx_buffer成员。启用DMA时对于传输，强烈建议使用这些缓冲区[...]

https://github.com/espressif/esp-idf/blob/master/docs/en/api-reference/peripherals/spi_master.rst

从指针读取值到结构中的指针（SPI事务）

0 个答案: