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AD9910 - Loading the RAM data files without Eval-board

Thread Summary

The user seeks to load RAM data files for a frequency sweep from 250 MHz to 350 MHz on an AD9910 device without an evaluation board. The solution involves using SPI to write start and end addresses to RAM Profile registers, selecting the profile via profile pins, and writing 32-bit frequency words to SPI address 0x16. Key clarifications include setting CFR3[15]=1 to bypass the REFCLK divide-by-2 block and verifying RAM data with RAM Enable set to 0 or 1.
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 Although it would be a fundamental question, let me ask one question. I want to know how to load the RAM data files without evaluation board.

 Above all, I want to introduce my procedures for loading the RAM data files with the evaluation board and software which were provided by Analog Device. Using evauation board and software, I successfully loaded the RAM data files and I could easily generate some ramp signals which I wanted. To be specific, several detailed conditions are mentioned below.

 - Fsystemclk = 1GHz

 - Start frequency = 250 MHz

 - End frequency = 350 MHz

 - frequency step = 0.1 MHz

 => RAM data files : 250MHz, 250.1MHz, 250.2MHz ~ 352 MHz, 352.1 MHz, 352.2 MHz

                                (# of data = 1024, I attached RAM data files which consists of Hex)

 I loaded these RAM data files using RAM I/O Window in the evaluation software. And then, Using Profiles Window, I designated each RA segment by setting Beginning and Final Address, step rate, and mode control.

 

 What I really want to know about is how I can load the RAM data files without Evaluation software and board. I want to know the similar procedure as I loaded attched text files in the RAM I/O Window when I used Eval-software. I think I might have to use SPI control pin such as SDIO, SCLK, I/O_RESET pins. Could you please let me know the detailed process for loading RAM data files?

250_350MHz.txt.zip
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  • Yes, you must use the SPI pins to communicate with the device in order to load data into the RAM (see the "Load/Retrieve RAM Operation" subsection of the "RAM Control" section of the datasheet).

    The basic procedure is as follows...

    1. Write the desired start and end addresses into the RAM Profile registers. Note each RAM Profile register defines a specific RAM segment (that is, RAM address range).
    2. Apply the appropriate logic levels to the Profile pins to select a particular RAM segment. This points the internal RAM controller to the appropriate address range in the RAM.
    3. Write to SPI address 0x16 the number of 32-bit words corresponding to the address range specified by the start and end addresses in the selected Profile. Note SPI address 0x16 serves as an external gateway to/from the RAM. The RAM controller takes each 32-bit word written to (or read from) SPI address 0x16 and transfers it to (or extracts it from) the appropriate address of the RAM. Note the controller "knows" how many 32-bit words to expect based on the start/end address values stored in the selected RAM Profile register. The SPI address 0x16 "gateway" is how you load or retrieve RAM data.

    The above procedure loads up the RAM segment with your data. Now you can "play back" the RAM contents to the desired destination (DDS frequency, phase or amplitude). The datasheet explains the various RAM playback modes, which you set up by programming the appropriate SPI registers. Note RAM "playback" is different from reading the RAM contents via the SPI address 0x16 gateway. Playback operation is an internal operation that "copies" the RAM segment data to the desired internal DDS parameter (frequency/phase/amplitude) at a specified "playback rate".

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  • Yes, you must use the SPI pins to communicate with the device in order to load data into the RAM (see the "Load/Retrieve RAM Operation" subsection of the "RAM Control" section of the datasheet).

    The basic procedure is as follows...

    1. Write the desired start and end addresses into the RAM Profile registers. Note each RAM Profile register defines a specific RAM segment (that is, RAM address range).
    2. Apply the appropriate logic levels to the Profile pins to select a particular RAM segment. This points the internal RAM controller to the appropriate address range in the RAM.
    3. Write to SPI address 0x16 the number of 32-bit words corresponding to the address range specified by the start and end addresses in the selected Profile. Note SPI address 0x16 serves as an external gateway to/from the RAM. The RAM controller takes each 32-bit word written to (or read from) SPI address 0x16 and transfers it to (or extracts it from) the appropriate address of the RAM. Note the controller "knows" how many 32-bit words to expect based on the start/end address values stored in the selected RAM Profile register. The SPI address 0x16 "gateway" is how you load or retrieve RAM data.

    The above procedure loads up the RAM segment with your data. Now you can "play back" the RAM contents to the desired destination (DDS frequency, phase or amplitude). The datasheet explains the various RAM playback modes, which you set up by programming the appropriate SPI registers. Note RAM "playback" is different from reading the RAM contents via the SPI address 0x16 gateway. Playback operation is an internal operation that "copies" the RAM segment data to the desired internal DDS parameter (frequency/phase/amplitude) at a specified "playback rate".

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