NRF52840 SPI cannot work

RE: NRF52840 SPI cannot work

ovrebekk — Mon, 25 Sep 2023 08:16:51 GMT

Checking the signals on a scope is very helpful, then you can get a lot more information about what is happening on the bus. If the voltage on the MOSI and MISO lines is 2.6V while VDD is 3V it points to some hardware connection issue, you would expect these lines to be either GND or VDD, not somewhere in between.

When you say the configuration has been verified elsewhere, you mean to say that you know that the mode, frequency and bit order should be correct?

Did you get your hardware design reviewed by us before you went to manufacturing?
We are happy to review your schematic and layout if you upload it here (if you do please open a new ticket though, as a hardware review would have to be performed by someone else).

Best regards
Torbjørn

RE: NRF52840 SPI cannot work

newspace — Tue, 19 Sep 2023 09:08:01 GMT

1. I use SDK 15. I suceeded to use SPI in another board.
2. I can only receive 0x00 from SPI no matter what is sent to it. I tried to configure some registers of the AFE but it didn't work. Maybe I should use an oscilloscope or logic analyzer to check the signals.
3. It's my custom board, not a DK.Another board is an ADS1299 of TI and NRF52840. I use P0.13, P0.15, P0.17 and P0.20.

The configuration of SPI:

nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.bit_order = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST; // unknown
spi_config.mode = NRF_DRV_SPI_MODE_1;
spi_config.frequency = NRF_DRV_SPI_FREQ_4M;
spi_config.irq_priority = APP_IRQ_PRIORITY_HIGH;

//spi_config.ss_pin = SPI_SS_PIN; //P0.13
spi_config.miso_pin = SPI_MISO_PIN; //P0.15
spi_config.mosi_pin = SPI_MOSI_PIN; //P0.17
spi_config.sck_pin = SPI_SCK_PIN; //P0.20
spi_config.orc = 0x54; // flag
APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));
NRF_LOG_INFO( "SPI INIT OK.\r\n");

RE: NRF52840 SPI cannot work

helsing — Tue, 19 Sep 2023 08:49:25 GMT

[quote user=""]What is the problem with my circuit?[/quote]

Let us look into this together. Would you be able to share some context? Which SDK version are you using? And which driver?

[quote user=""]SPI doesn't work[/quote]

How do you verify that SPI is not working? Do you have any logs available from the terminal? Have you inspected the signal using an oscilloscope or logic analyzer?

[quote user=""]the configurations have been verified elsewhere[/quote]

How have you configured this and the other project? Are you using a DK or a custom board? Which pins are you using?