Issue creating and using binding files for SPI

RE: Issue creating and using binding files for SPI

HarrisonBrown — Thu, 06 Mar 2025 01:46:50 GMT

Hi Hieu,

I have managed to get the SPI driver to at least stop producing an error on build and I think I now understand the bindings.

I am currently not producing any SPI SCLK or MOSI on my logic analyser right now but that is another issue.

The main issue behind this ticket is solved, thank you.

RE: Issue creating and using binding files for SPI

HarrisonBrown — Wed, 05 Mar 2025 19:07:25 GMT

Thank you for your answer, I have dug through the zephyr and cmake documentation and through long hours have somehow managed to get a grip on the errors I have caused and why.

Yes, I cannot change a required to not required, and errant spaces are an issue!

I am in the process of getting my SPI driver running now, and will highlight your reply as an answer if I have things functioning.

RE: Issue creating and using binding files for SPI

HarrisonBrown — Wed, 05 Mar 2025 19:05:28 GMT

FYI, I have some clarification and proof about the multibyte delay:

9.5.2.9: ADS129x Datasheet

However, if SCLK is 4 MHz, one byte is transferred in 2 µs. Because this transfer time exceeds the tSDECODE specification, the processor can send subsequent bytes without delay. In the second scenario, the serial port can be programmed to use multiple byte transfers instead of the single-byte transfers required to meet the timing of the first scenario.

I have scoped the ADS1298 PDK running using the TI evaluation software.

The attached image shows the PDK outputting a two byte command read and getting a response whilst using a 4MHz clock. The need to run with a 4* t_CLK space is not required. I would assume that the ADS129x spi rx register can still receive spi data but cannot act upon the next byte received within 4* t_CLK, this clarifies this section.

RE: Issue creating and using binding files for SPI

Hieu — Wed, 05 Mar 2025 13:28:15 GMT

The error says that there is a conflict of the spi-max-frequency > required key between your file and a file it includes.

As spi-device.yaml is the only file you have included, we only need to check there.

Notice how in spi-device.yaml, the spi-max-frequency > required key is true, but in your file, it is false. This conflict is not allowed.

This is not allowed. You will need to set spi-max-frequency > required to true

RE: Issue creating and using binding files for SPI

HarrisonBrown — Tue, 04 Mar 2025 16:53:07 GMT

That is certainly a good idea suspending the task. Hopefully I will have time to try that and let you know. running at a higher clock speed would be nice to reduce power.

RE: Issue creating and using binding files for SPI

HarrisonBrown — Tue, 04 Mar 2025 16:48:53 GMT

Changing reg type from int to array then brought an error for spi-max-frequency:

devicetree error: D:/_HONS/nRF_Projects/ads1298test1/dts/bindings\sensor\ti,ads1298.yaml (in 'spi-max-frequency'): 'required' from included file overwritten ('True' replaced with 'False')

It seems I am missing some knowledge on editing binding files as even this change is throwing an error?

RE: Issue creating and using binding files for SPI

HarrisonBrown — Tue, 04 Mar 2025 16:46:15 GMT

Hi Hieu,

That is correct there were errant spaces, I'll bear in mind those are an issue, probably there from me commenting out sections when retying.

Removing those spaces provided a different error:

I can see I have replaced reg with an int instead of an array in the binding.devzone.nordicsemi.com/.../1_2D00_2-spaces-removed-from-binding.txt

RE: Issue creating and using binding files for SPI

hmolesworth — Tue, 04 Mar 2025 16:36:26 GMT

Another alternative is using SPIM TASKS_SUSPEND and TASKS_RESUME coupled via PPI to a timer to provide the required delay which then allows a much higher clock speed. I never got around to trying that.

RE: Issue creating and using binding files for SPI

HarrisonBrown — Tue, 04 Mar 2025 16:21:07 GMT

Hi hmolesworth,

This support is a veritable mountain of info, much appreciated. Its the same situation and setup as myself. I am fully aware of the power on sequence and have hopefully already accounted for the 4xtclk delay mentioned in this thread. I too plan on manually controlling \CS within a function to account for this delay but lowering the SCLK to 500kHz is a good idea. Hopefully my test sequence works better than the OP, I have already accounted power on time but should probably monitor the AVDD and DVDD.

RE: Issue creating and using binding files for SPI

hmolesworth — Tue, 04 Mar 2025 03:15:01 GMT

There are other considerations when using the ADS1298, which you may not be aware of yet; this is unrelated to your direct question but I think will be helpful in moving forward. Have a look at this ticket; I provided some support on the old SDK but the information should be useful.

problem-using-the-nrf52840-to-interface-an-ads1298-via-spi

RE: Issue creating and using binding files for SPI

Hieu — Tue, 04 Mar 2025 00:03:13 GMT

Hi HarrisonBrown,

I am not certain if this is a website format or copy paste error, but there is an invalid indent of 1 space on line 13 and 25 of your YAML file. This invalid indent on line 13 would check out with the error log.

If the indent is actually in your file, could you please remove them and retry?

Hieu

RE: Issue creating and using binding files for SPI

HarrisonBrown — Mon, 03 Mar 2025 00:10:02 GMT

devzone.nordicsemi.com/.../Issue-creating-or-using-bindings-for-SPI.txt

Please see attached txt file with logs and overlay code, apologies but the text limit appears not to like me.

RE: Issue creating and using binding files for SPI

HarrisonBrown — Mon, 03 Mar 2025 00:07:21 GMT

I am also unable to reply with more than a few lines without an error, please bear with me.

# ti,ads1298.yaml
# Put this in the project\dts\bindings\sensor folder
# Make one if it doesnt exist

description: |
  The ADS1298 is a 8-channel, 24-bit analog front-end for measuring
  electrophysiological signals such as ECG or EEG.

compatible: "ti,ads1298"

include: [spi-device.yaml]

 properties:
  reg:
    type: int
    required: true
    description: |
      reg is the SPI Mode MODE 1 FOR THIS DEVICE

  spi-max-frequency:
    type: int
    required: false
    description: |
      SCLK maximum frequency: 20MHz at DVDD 2.7-3.6V and 15MHz for 1.65-2V

 drdy-gpios:
    type: phandle-array
    required: false
    description: |
      Active Low Data Ready pin indicating when data is ready to be read

When I build this project I notice a warning in the log:
appears in binding directories but isn't valid YAML: while parsing a block mapping in "<unicode string>", line 5, column 1 did not find expected key in "<unicode string>", line 13, column 2