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Page 9 of 16

Page 229

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/spi_common.h"
#include "driver/spi_master.h"

void app_main(void)
{
    spi_bus_config_t busConfig = {
        .sclk_io_num = 14,
        .mosi_io_num = 13,
        .miso_io_num = 12,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
    };
    spi_bus_initialize(SPI2_HOST, &busConfig, SPI_DMA_DISABLED);

    spi_device_interface_config_t masterConfig = {
        .command_bits = 0,
        .address_bits = 0,
        .dummy_bits = 0,
        .mode = 0,
        .queue_size = 10,
        .clock_speed_hz = SPI_MASTER_FREQ_8M,
        .spics_io_num = 15,
    };
    spi_device_handle_t SPI = NULL;
    spi_bus_add_device(SPI2_HOST, &masterConfig, &SPI);

    spi_transaction_t transConfig = {
        .length = 8 * 4,
        .flags = SPI_TRANS_USE_RXDATA | SPI_TRANS_USE_TXDATA,
        .tx_data = {0xAA, 0xAA, 0xAA, 0xAA},
    };
    spi_device_polling_transmit(SPI, &transConfig);

    printf("received %X %X %X %X\n", transConfig.rx_data[0],
           transConfig.rx_data[1], transConfig.rx_data[2],
           transConfig.rx_data[3]);
}

 

Page 235

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/spi_common.h"
#include "driver/spi_master.h"

void app_main(void)
{
    spi_bus_config_t busConfig = {
        .sclk_io_num = 14,
        .mosi_io_num = 13,
        .miso_io_num = 12,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
    };
    spi_bus_initialize(SPI2_HOST, &busConfig, SPI_DMA_DISABLED);

    spi_device_interface_config_t masterConfig = {
        .command_bits = 0,
        .address_bits = 0,
        .dummy_bits = 0,
        .mode = 0,
        .queue_size = 10,
        .clock_speed_hz = 500000,
        .spics_io_num = 15,
    };
    spi_device_handle_t SPI = NULL;
    spi_bus_add_device(SPI2_HOST, &masterConfig, &SPI);

    spi_transaction_t transConfig = {
        .flags = SPI_TRANS_USE_RXDATA | SPI_TRANS_USE_TXDATA,
    };
    transConfig.tx_data[0] = 0x01;
    transConfig.tx_data[1] = 0x80;
    transConfig.tx_data[2] = 0x00;
    transConfig.length = 8 * 3;
    while (true)
    {
        spi_device_polling_transmit(SPI, &transConfig);
        printf("received %X %X %X %X\n", transConfig.rx_data[0],
               transConfig.rx_data[1], transConfig.rx_data[2],
               transConfig.rx_data[3]);
        int data = (transConfig.rx_data[1] & 0x03) << 8 |
                   transConfig.rx_data[2];
        float volts = data * 3.3 / 1023.0;
        printf("%f\n", volts);
        fflush(stdout);
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}

 

Page 236-237 from fragments

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "driver/spi_common.h"
#include "driver/spi_master.h"

spi_device_handle_t SPI_init()
{
  spi_bus_config_t busConfig = {
    .sclk_io_num = 14,
    .mosi_io_num = 13,
    .miso_io_num = 12,
    .quadwp_io_num = -1,
    .quadhd_io_num = -1,
  };
  spi_bus_initialize(SPI2_HOST, &busConfig, SPI_DMA_DISABLED);

  spi_device_interface_config_t masterConfig = {
   .command_bits = 0,
   .address_bits = 0,
   .dummy_bits = 0,
   .mode = 0,
   .queue_size = 10,
   .clock_speed_hz = 500000,
   .spics_io_num = 15,
  };
  spi_device_handle_t SPI = NULL;
  spi_bus_add_device(SPI2_HOST, &masterConfig, &SPI);
  return SPI;
}

float readADC(spi_device_handle_t SPI, uint8_t chan)
{
  spi_transaction_t transConfig = {
     .flags = SPI_TRANS_USE_RXDATA | SPI_TRANS_USE_TXDATA,
  };
  transConfig.tx_data[0] = 0x01;
  transConfig.tx_data[1] = (0x08 | chan) << 4;
  transConfig.tx_data[2] = 0x00;
  transConfig.length = 8 * 3;
  spi_device_polling_transmit(SPI, &transConfig);
  int data = (transConfig.rx_data[1] & 0x03) << 8 |
                                  transConfig.rx_data[2];
  float volts = data * 3.3 / 1023.0;
  return volts;
}

void app_main(void)
{
  spi_device_handle_t SPI = SPI_init();
  while (true) {
    float volts = readADC(SPI, 0);
    printf("%f\n", volts);
    fflush(stdout);
    vTaskDelay(1000 / portTICK_PERIOD_MS);
  }
}