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ADS1299EEGFE-PDK：ADS1299EEGFE-PDK

Junzhe Zhang
Prodigy 130 points
Part Number: ADS1299EEGFE-PDK
Other Parts Discussed in Thread: ADS1299,

Tool/software:

Hello everyone.

I want to use ADS1299 to develop EEG devices. So I bought ADS1299EEGFE-PDK, which I think is easier to use. I want to control it with STM32 processor. I would like to ask, is it feasible to connect the test board to MMB0, powered by MMB0 and controlled by stm32?

But I seem to have encountered some problems and I am troubleshooting. I can't read the default register value of ADS1299 on the test board through SPI instructions. I'm not sure if I damaged the board. I want to know if there is any way to verify that the board is intact? Can I judge whether the board is intact by the voltage of these TPs?

Current jumper configurations:

JP1: open

JP2: 2-3

JP4: 1-2  

JP6: 1-2

JP7: 1-2

JP8: 1-2

JP17: open

JP18: 2-3

JP19: 1-2

JP20: 1-2

JP21: 1-2

JP22: 2-3

JP23: 1-2

JP24: 2-3

Is there anything glaringly wrong with this setup?

Also, I want to know, when I want to use the 2.048Mhz crystal on the ADS1299EEGFE-PDK board, how should I set the jumpers JP18 and JP23?

The JP18 should be 2-3, JP23 should be 1-2？

But in the circuit diagram, if JP18 is connected as 2-3 (The middle and lower terminals of the three terminals), does it mean that EXT_CLK is used?

And I also want to know, ADS1299 is using internal crystal, crystal on EVM, or external crystal. Will different crystal frequencies affect SPI communication?

Thanks a lot for it.

  • 0
    Prodigy 130 points

    In addition, is there a better way to distinguish the corresponding relationship between different jumper connectors, especially when there are three connectors (such as JP18, JP21, JP22, JP23, etc.), how to tell which is 1, 2, and 3? Because some of them are horizontal and some are vertical, which makes me feel a little confused.

  • 0 in reply to Junzhe Zhang
    TI__Guru 66246 points

    Hello Junzhe,

    Thank you for your post and your interest in using our ADS1299.

    Our support for interfacing the EVM-PDK hardware with an external controller like the STM32 is very limited due to the complexities of each user's unique setup. However, it is certainly possible. I would make the following suggestions to simplify the setup:

    1. Physically separate the MMB0 and EVM daughterboard. If using the MMB0 to provide analog and digital power supplies, then it's best to flywire the necessary connections for GND, +5V, and DVDD (1.8V or 3.3V). This ensures that no digital signals from the external MCU are interfered with by the DSP on the MMB0.
    2. Connect the necessary SPI signals from the MCU to the most direct header pin or test point available. For example, /CS can connect to JP21[2] (without a jumper installed). Most I/O signals can be found on J3.
    3. The ADS1299 can still be used with an internal or external oscillator. The selection can be made via JP23 ([1-2] = external, [2-3] or OFF = internal).

    FYI - in the schematic, the "rounded" corners of the header schematic symbol indicate pin 1. On the PCB, pin 1 is denoted by a square pad, while the remaining pins feature a circular pad.

    Regards,

    Ryan

  • 0 in reply to Ryan Andrews
    Prodigy 130 points

    Hi Ryan

    Thanks for clarifying here how the ADS1299 EVM is connected to MMB0 and how the jumper on the ADS1299 EVM is arranged, that is very helpful.

    When I want to read the register value inside ADS1299, it seems that it cannot be read successfully, and the returned value is always 0x00. I used a logic analyzer to detect the logic relationship of the corresponding pins as shown in the figure.

    Channel 0 is CS, channel 1 is SCLK, channel 2 is MISO, and channel 3 is MOSI. Do they look normal? I don't know if it's because the ADS1299 EVM is damaged, causing the SPI transmission to be unable to read its register values. I measured the voltages of the corresponding TP terminals in the user manual, and they look normal. Is there any way to detect whether the ADS1299 EVM is damaged?

    Regards,

    Junzhe

  • 0 in reply to Junzhe Zhang
    TI__Guru 66246 points

    Hi Junzhe,

    Have you issued an SDATAC command before the RREG command? Please refer to 9.5.3 of the device data sheet.

    Regards,

    Ryan

  • 0 in reply to Ryan Andrews
    Prodigy 130 points

    Hi Ryan,

    This is my code for stm32. I use the SDATAC code before RREG. But I can not get the register value back to the serial port. Is there any problem in this code?

    This is what I get from the serial port output.

    And this is SPI output waveform from STM32 measured by logic analyzer.

    Kind regards

    Junzhe

  • 0 in reply to Junzhe Zhang
    Prodigy 130 points

    Make them easier to see.

  • 0 in reply to Junzhe Zhang
    Prodigy 130 points

    CH0: CS CH1: SCLK CH2: MISO CH3 MOSI