AD400X no-OS driver

Supported Devices

Overview

The AD4000/AD4001/AD4002/AD4003/AD4020 family of evaluation boards enable quick, simplified evaluation of the AD4000 family of 16-/18-/20-bit, precision successive approx-imation register (SAR) analog-to-digital converters (ADCs). The AD4000/AD4001/AD4002/AD4003/AD4020 are low power, 16-bit/18-bit/20-bit, precision SAR ADCs that offer high performance with throughputs up to 2 MSPS (1.8 MSPS for the AD4020). The evaluation board demonstrates the performance of the AD4000/AD4001/AD4002/AD4003/AD4020 family of ADCs and provides a simplified interface for a variety of system applications.

AD400X Device Configuration

Driver Initialization

ad400x_init is called with the settings dma, pwm, clkgen, and the 4 gpios to set the operation mode.

ad400x_remove Free the allocated resources

ad400x_spi_reg_write called to write a register

ad400x_spi_reg_read called to read a register

ad400x_read_data called to fill a buffer with n number of samples.

AD400X Driver Initialization Example

struct no_os_spi_init_param ad400x_spi_init = {
        .device_id = SPI_DEVICE_ID,
        .chip_select = SPI_CS,
        .max_speed_hz = SPI_BAUDRATE,
        .mode = NO_OS_SPI_MODE_0,
        .platform_ops = SPI_OPS,
        .extra = (void*)SPI_EXTRA,
};

struct spi_engine_offload_init_param spi_engine_offload_init_param = {
        .offload_config = OFFLOAD_RX_EN,
        .rx_dma_baseaddr = DMA_BASEADDR,
};

struct axi_clkgen_init clkgen_init = {
        .name = "rx_clkgen",
        .base = RX_CLKGEN_BASEADDR,
        .parent_rate = 100000000,
};

struct no_os_pwm_init_param trigger_pwm_init = {
        .period_ns = PWM_PERIOD,
        .duty_cycle_ns = PWM_DUTY,
        .polarity = NO_OS_PWM_POLARITY_HIGH,
        .platform_ops = PWM_OPS,
        .extra = PWM_EXTRA,
};

struct no_os_gpio_init_param gpio_cnv = {
        .port = GPIO_CNV_PORT,
        .pull = NO_OS_PULL_NONE,
        .number = GPIO_CNV,
        .platform_ops = GPIO_OPS,
};

struct ad400x_init_param ad400x_init_param = {
        .dev_id = ID_AD4020,
        .spi_init = &ad400x_spi_init,
        .trigger_pwm_init = &trigger_pwm_init,
        .clkgen_init = &clkgen_init,
        .axi_clkgen_rate = REFCLK_RATE,
        .reg_access_speed = 1000000,
        .offload_init_param = &spi_engine_offload_init_param,
        .dcache_invalidate_range = DCACHE_INVALIDATE,
        .gpio_cnv = &gpio_cnv,
        .offload_enable = 1,
        .turbo_mode = 1,
        .high_z_mode = 0,
        .span_compression = 0,
        .en_status_bits = 0,
}

struct ad400x_dev *dev;
uint32_t data[1000];
int32_t ret, i;
uint16_t resolution;
char sign;

ret = ad400x_init(&dev, &ad400x_init_param);
if (ret)
        return ret;

sign = dev->dev_info->sign;
resolution = dev->dev_info->resolution;

ret = ad400x_read_data(dev, data, 1000);
if (ret) {
        pr_info("Error: ad400x_read_data: %ld\n", ret);
        ad400x_remove(dev);
        return ret;
}

for(i = 0; i < 1000; i++) {
        if (sign == 's')
                printf("ADC: %ld\n\r", no_os_sign_extend32(data[i], resolution - 1));
        else
                printf("ADC: %ld\n\r", data[i]);
}

AD400X no_OS IIO Support

The AD400X uses the iio_ad400x driver for iio support.

ad400x specific IIO Initialization

ad400x_iio_init is called with a ad400x_iio_init_param structure that contains the ad400x_init_param plus iio specific parameters

ad400x_iio_remove Free the allocated resources

AD400X IIO Driver Initialization Example

struct no_os_spi_init_param ad400x_spi_init = {
        .device_id = SPI_DEVICE_ID,
        .chip_select = SPI_CS,
        .max_speed_hz = SPI_BAUDRATE,
        .mode = NO_OS_SPI_MODE_0,
        .platform_ops = SPI_OPS,
        .extra = (void*)SPI_EXTRA,
};

struct spi_engine_offload_init_param spi_engine_offload_init_param = {
        .offload_config = OFFLOAD_RX_EN,
        .rx_dma_baseaddr = DMA_BASEADDR,
};

struct axi_clkgen_init clkgen_init = {
        .name = "rx_clkgen",
        .base = RX_CLKGEN_BASEADDR,
        .parent_rate = 100000000,
};

struct no_os_pwm_init_param trigger_pwm_init = {
        .period_ns = PWM_PERIOD,
        .duty_cycle_ns = PWM_DUTY,
        .polarity = NO_OS_PWM_POLARITY_HIGH,
        .platform_ops = PWM_OPS,
        .extra = PWM_EXTRA,
};

struct no_os_gpio_init_param gpio_cnv = {
        .port = GPIO_CNV_PORT,
        .pull = NO_OS_PULL_NONE,
        .number = GPIO_CNV,
        .platform_ops = GPIO_OPS,
};

struct ad400x_init_param ad400x_init_param = {
        .dev_id = ID_AD4020,
        .spi_init = &ad400x_spi_init,
        .trigger_pwm_init = &trigger_pwm_init,
        .clkgen_init = &clkgen_init,
        .axi_clkgen_rate = REFCLK_RATE,
        .reg_access_speed = 1000000,
        .offload_init_param = &spi_engine_offload_init_param,
        .dcache_invalidate_range = DCACHE_INVALIDATE,
        .gpio_cnv = &gpio_cnv,
        .offload_enable = 1,
        .turbo_mode = 1,
        .high_z_mode = 0,
        .span_compression = 0,
        .en_status_bits = 0,
}

struct iio_data_buffer adc_buff = {
        .buff = (void *)ADC_DDR_BASEADDR,
        .size = MAX_SIZE_BASE_ADDR,
};

struct ad400x_iio_init_param ad400x_iio_ip = {
        .init_param = &ad400x_init_param,
        .ref_voltage_mv = AD400X_ADC_REF_VOLTAGE,
};

struct ad400x_iio_dev *dev;
struct iio_app_init_param app_init_param = {0};
struct iio_app_desc *app;
int ret;

ret = ad400x_iio_init(&dev, &ad400x_iio_ip);
if (ret)
        return ret;

struct iio_app_device iio_devices[] = {
        IIO_APP_DEVICE( "ad400x", dev,
                        dev->iio_dev, &adc_buff, NULL, NULL)
};

app_init_param.devices = iio_devices;
app_init_param.nb_devices = NO_OS_ARRAY_SIZE(iio_devices);
app_init_param.uart_init_params = ad400x_uart_ip;

ret = iio_app_init(&app, app_init_param);
if (ret) {
        pr_info("Error: iio_app_init: %d\n", ret);
        ad400x_iio_remove(dev);
        return ret;
}

ret = iio_app_run(app);
if (ret)
        pr_info("Error: iio_app_run: %d\n", ret);

iio_app_remove(app);

ad400x_iio_remove(dev);

return ret;