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drivers: adc: ad9434: Add README doc for AD9434
Added the rst readme document for the AD9434 driver. Also modified the drivers_doc.rst to add the corresponding source for this new readme. Signed-off-by: Joyce Velasco <[email protected]>
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‎doc/sphinx/source/drivers/adc/ad9434.rst‎

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.. include:: ../../../../drivers/adc/ad9434/README.rst

‎drivers/adc/ad9434/README.rst‎

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AD9434 no-OS driver
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===================
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Supported Devices
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-----------------
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- :adi:`AD9434`
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Overview
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--------
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The AD9434 is a high-performance 12-bit ADC designed for applications
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demanding fast conversion rates up to 500 MSPS. It integrates essential
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features such as a sample-and-hold circuit and voltage reference
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on-chip, ensuring comprehensive signal conversion. This ADC requires a
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1.8 V analog supply and uses a differential clock for optimal
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functionality. Its digital output is compatible with LVDS standards,
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supporting formats including twos complement, offset binary, or Gray
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code. Additionally, it features a data clock output for accurate data
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timing. Available in a 56-lead LFCSP, the AD9434 is suitable for
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industrial environments with temperatures ranging from -40°C to +85°C.
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Applications
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------------
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- Wireless and wired broadband communications
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- Cable reverse path
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- Communications test equipment
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- Radar and satellite subsystems
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- Power amplifier linearization
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Operation Modes
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----------------
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+--------------------------+-----------------+-----------------+-----------------+
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| Mode Name | Description | Configuration | Typical Use |
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| | | Bits | Case |
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+--------------------------+-----------------+-----------------+-----------------+
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| OUTPUT_MODE_E | Represents the | 0x0 | General ADC |
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| _OFFSET_BINARY | output mode for | | operation using |
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| | the ADC when | | offset binary |
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| | configured to | | output. |
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| | use offset | | |
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| | binary format. | | |
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+--------------------------+-----------------+-----------------+-----------------+
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| OUTPUT_MODE | Represents the | 0x1 | General ADC |
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| _TWOS_COMPLEMENT | two’s | | operation using |
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| | complement | | two’s |
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| | output mode for | | complement |
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| | the ADC. | | output. |
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+--------------------------+-----------------+-----------------+-----------------+
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| OUTPUT_MODE_GRAY_CODE | Represents the | 0x2 | Used in |
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| | gray code | | applications |
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| | output mode for | | requiring |
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| | the ADC. | | gray-coded |
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| | | | output. |
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+--------------------------+-----------------+-----------------+-----------------+
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| OUTPUT_EVEN_ODD_MODE_EN | Enable even-odd | 0x20 | Used when |
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| | output mode in | | alternating |
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| | the ADC’s | | even and odd |
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| | output phase | | outputs is |
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| | register. | | required. |
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+--------------------------+-----------------+-----------------+-----------------+
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| TESTMODE_OFF | Indicates that | 0x0 | Standard |
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| | the test mode | | operation |
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| | for the ADC is | | without test |
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| | turned off. | | modes. |
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+--------------------------+-----------------+-----------------+-----------------+
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| TESTMODE_MIDSCALE_SHORT | Configures the | 0x1 | Testing ADC |
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| | ADC for a | | functionality |
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| | midscale short | | at midscale. |
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| | test mode. | | |
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+--------------------------+-----------------+-----------------+-----------------+
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| TESTMODE_POS_FULLSCALE | Positive | 0x2 | Verify ADC |
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| | full-scale test | | response at |
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| | mode. | | positive full |
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| | | | scale. |
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+--------------------------+-----------------+-----------------+-----------------+
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| TESTMODE_NEG_FULLSCALE | Negative | 0x3 | Verify ADC |
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| | full-scale test | | response at |
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| | mode. | | negative full |
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| | | | scale. |
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+--------------------------+-----------------+-----------------+-----------------+
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| TESTMODE_ALT_CHECKERBOARD| Enables an | 0x4 | Testing ADC |
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| | alternating | | with a |
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| | checkerboard | | checkerboard |
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| | pattern in test | | pattern input. |
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| | mode. | | |
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+--------------------------+-----------------+-----------------+-----------------+
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| TESTMODE_PN23_SEQ | PN23 sequence | 0x5 | Using PN23 |
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| | test mode. | | sequences for |
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| | | | ADC testing. |
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+--------------------------+-----------------+-----------------+-----------------+
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Device Configuration
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---------------------
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Device Management
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~~~~~~~~~~~~~~~~~
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The ``ad9434_setup`` function is responsible for initializing the AD9434
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ADC device. It begins by allocating memory for an ``ad9434_dev``
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structure, which represents the device context, and initializes SPI
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communication using the settings provided in the ``ad9434_init_param``
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structure. The function verifies the communication by reading the chip
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ID from the device and comparing it with the expected
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``AD9434_CHIP_ID``. If the ID does not match, it returns an error with a
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status code of -1. Following successful verification, the default output
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mode is configured using ``ad9434_outputmode_set``. The memory
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allocation and SPI initialization must succeed for the function to
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complete, with each step’s result contributing to the final return
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value. The initialized ``ad9434_dev`` structure is then assigned to the
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provided device pointer, and a success message is printed upon
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successful execution, returning 0 to indicate success or -1 upon
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failure.
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SPI Communication
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~~~~~~~~~~~~~~~~~
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Key to the AD9434 driver’s functionality are the SPI communication
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operations, ``ad9434_spi_read`` and ``ad9434_spi_write``. These
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functions handle low-level reading and writing of the ADC’s registers
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over SPI, facilitating both configuration and data acquisition.
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``ad9434_spi_read`` constructs a read command, while
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``ad9434_spi_write`` sends data to specified registers, both reporting
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operation status.
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Output Mode and Test Configuration
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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The driver enables output mode adjustments and test scenarios through
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functions like ``ad9434_outputmode_set`` and ``ad9434_testmode_set``.
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``ad9434_outputmode_set`` writes the required configuration to the
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output register for proper data formatting, whereas
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``ad9434_testmode_set`` configures the ADC into various test modes by
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writing specific values to the test register. These functions allow
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customization of the ADC for diverse application needs.
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Data Delay and Phase Adjustment
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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To enhance ADC performance, the driver offers the ``ad9434_data_delay``
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function to adjust output data delay, synchronizing with system
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components by writing to the delay register. Macros for phase and offset
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adjustments are defined, though specific functions for these were not
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detailed in the content provided. These settings enable precise control
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for optimized ADC functioning across various conditions.
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Driver Initialization Example
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-----------------------------
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.. code-block:: C
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include "no_os_spi.h"
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#include "no_os_delay.h"
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#include "no_os_alloc.h"
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#include "ad9434.h"
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struct ad9434_dev *device;
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int32_t ret;
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struct ad9434_init_param init_param = {
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.spi_init = {
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.device_id = 0,
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.max_speed_hz = 10000000u,
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.chip_select = 0,
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.mode = NO_OS_SPI_MODE_0,
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.platform_ops = &xil_spi_ops,
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.extra = &xil_spi_init_param,
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}
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};
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ret = ad9434_setup(&device, init_param);
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if (ret)
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goto err;
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printf("AD9434 initialization successful\n");
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goto done;
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err:
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printf("AD9434 initialization failed with error: %ld\n", ret);
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done:
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;
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IIO Support
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-----------
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IIO Device Initialization
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~~~~~~~~~~~~~~~~~~~~~~~~~
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To efficiently manage the setup of IIO devices using the AD9434, the
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initialization begins with the ``ad9434_setup`` function. This function
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allocates an ``ad9434_dev`` structure to establish the device context,
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involving SPI setup parameters for communication. It checks the chip ID
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via ``ad9434_spi_read`` and sets the default output mode through SPI
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writes. The ``iio_axi_adc_init`` function is responsible for
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initializing the IIO device. It takes parameters such as the
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``iio_axi_adc_desc`` and initializes them with the structures like
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``iio_axi_adc_init_param``, which encompasses ADC and DMAC cores and
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cache invalidation settings.
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Upon any failure, error codes prompt the ``ad9434_remove`` function,
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which cleans up resources by deallocating memory and releasing SPI
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components. Error handling via return codes is essential for device
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integrity.
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IIO Application Execution
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~~~~~~~~~~~~~~~~~~~~~~~~~
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The ``iio_app_init`` function sets up the IIO application, incorporating
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UART initialization parameters from ``no_os_uart_init_param``. Running of
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the IIO app is handled by ``iio_app_run``, using settings defined in
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``iio_app_init_param``, including buffer details for data access. These
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functions collectively manage the complete life cycle of IIO device
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initialization and configuration, ensuring seamless communication and
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data processing for the AD9434.
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IIO Device Initialization Example
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---------------------------------
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.. code-block:: C
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struct xil_uart_init_param platform_uart_init_par = {
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.type = UART_PS,
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.irq_id = UART_IRQ_ID
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};
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struct no_os_uart_init_param iio_uart_ip = {
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.device_id = UART_DEVICE_ID,
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.irq_id = UART_IRQ_ID,
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.baud_rate = UART_BAUDRATE,
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.size = NO_OS_UART_CS_8,
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.parity = NO_OS_UART_PAR_NO,
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.stop = NO_OS_UART_STOP_1_BIT,
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.extra = &platform_uart_init_par,
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.platform_ops = &xil_uart_ops
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};
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struct iio_axi_adc_desc *iio_axi_adc_desc;
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struct iio_device *dev_desc;
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struct iio_axi_adc_init_param iio_axi_adc_init_par;
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iio_axi_adc_init_par = (struct iio_axi_adc_init_param) {
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.rx_adc = ad9434_core,
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.rx_dmac = ad9434_dmac,
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.dcache_invalidate_range = (void (*)(uint32_t,
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uint32_t))Xil_DCacheInvalidateRange
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};
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struct iio_app_desc *app;
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struct iio_app_init_param app_init_param = { 0 };
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status = iio_axi_adc_init(&iio_axi_adc_desc, &iio_axi_adc_init_par);
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if (status < 0)
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return status;
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iio_axi_adc_get_dev_descriptor(iio_axi_adc_desc, &dev_desc);
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struct iio_data_buffer read_buff = {
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.buff = (void *)ADC_DDR_BASEADDR,
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.size = 0xFFFFFFFF,
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};
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struct iio_app_device devices[] = {
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IIO_APP_DEVICE("ad9434_dev", iio_axi_adc_desc, dev_desc,
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&read_buff, NULL, NULL),
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};
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app_init_param.devices = devices;
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app_init_param.nb_devices = NO_OS_ARRAY_SIZE(devices);
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app_init_param.uart_init_params = iio_uart_ip;
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status = iio_app_init(&app, app_init_param);
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if (status)
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return status;
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return iio_app_run(app);

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