NRF9160 SPI Clock Frequency Config

RE: NRF9160 SPI Clock Frequency Config

nikhil honeywell — Tue, 03 Aug 2021 06:19:29 GMT

Hi Carl & Team,

I am moving this case to private @ Case ID: 274304.

Thanks for the support !

RE: NRF9160 SPI Clock Frequency Config

Carl Richard — Wed, 28 Jul 2021 14:54:04 GMT

Hello again!

It's challenging to review code like this, but from what I can see it looks okay to me. Isn't it working? How is your device tree overlay configured?

Note that the nRF9160 supports a maximum of 8MHz over SPI.

Best regards,
Carl Richard

RE: NRF9160 SPI Clock Frequency Config

nikhil honeywell — Wed, 28 Jul 2021 13:59:35 GMT

Hi Carl and Team,
I have below design approach to interface NOR-Flash on SPI3 which supports up to 33MHz.
Could you verify this and give suitable advice.

// eFLASH SPI:
#define EFLASH_SPI_CH "SPI_3" // SPI channel-3
#define EFLASH_SPI_FREQ 400000 //400000 //1000000 // 1MHz

// eFLASH SPI's CS pin:
#define EFLASH_SPICS_NODE DT_ALIAS(flashspics)
#define EFLASH_SPICS DT_GPIO_LABEL(EFLASH_SPICS_NODE, gpios)
#define EFLASH_SPICS_PIN DT_GPIO_PIN(EFLASH_SPICS_NODE, gpios) // pin-15
#define EFLASH_SPICS_FLAGS DT_GPIO_FLAGS(EFLASH_SPICS_NODE, gpios)

static struct spi_cs_control eFlash_spi_css;
static struct device* eFlash_spi_dev;
static struct spi_config eFlash_spi_cfg;

static uint8_t eFlash_tx_buffer[261];
static struct spi_buf eFlash_tx_buf = {
.buf = eFlash_tx_buffer,
.len = 1,
};
static struct spi_buf_set eFlash_tx = {
.buffers = &eFlash_tx_buf,
.count = 1,
};

static uint8_t eFlash_rx_buffer[261];
static struct spi_buf eFlash_rx_buf = {
.buf = eFlash_rx_buffer,
.len = 1,
};
static struct spi_buf_set eFlash_rx = {
.buffers = &eFlash_rx_buf,
.count = 1,
};

uint8_t eFlash_spiInit(void) {
eFlash_spi_css.gpio_dev = device_get_binding(EFLASH_SPICS);
eFlash_spi_css.gpio_pin = EFLASH_SPICS_PIN;
eFlash_spi_css.delay = 1; // 1msec
eFlash_spi_css.gpio_dt_flags = GPIO_ACTIVE_LOW;

eFlash_spi_dev = device_get_binding(EFLASH_SPI_CH);
if (eFlash_spi_dev == NULL) {
//printk("Could not get %s device\n", EFLASH_SPI_CH);
return 1; // error, SPI device binding error
}

eFlash_spi_cfg.operation = (SPI_WORD_SET(8) | SPI_TRANSFER_MSB | SPI_OP_MODE_MASTER);// | SPI_MODE_CPOL | SPI_MODE_CPHA );
eFlash_spi_cfg.frequency = EFLASH_SPI_FREQ;
eFlash_spi_cfg.slave = 0;
eFlash_spi_cfg.cs = &eFlash_spi_css;

return 0; // success, no error configuring SPI parameters
}

uint8_t eFlash_spiTxRx(void) {
int32_t error;
error = spi_transceive(eFlash_spi_dev, &eFlash_spi_cfg, &eFlash_tx, &eFlash_rx);
if (error != 0) {
//printk("spi_transceive error: %d\n", error);
return 1; // error, SPI transceive error
}
else {
return 0; // success transceive data on SPI
}
}

RE: NRF9160 SPI Clock Frequency Config

Carl Richard — Wed, 28 Jul 2021 13:28:11 GMT

Hi again, Nikhil!

I had a talk with Lorenzo about this issue. Let's try to figure this out! Firstly, what does your Device Tree overlay file look like? It's important that the clock-frequency parameter is large enough. I understood that you where wondering where the clock is sourced from as well and that would be the HFCLK.

Could you try to test with this SPI sample? I just tried it and achieved 4MHz frequency without any issues.

If you get any errors or similar please share your build folder and the error messages.

Best regards,
Carl Richard

RE: NRF9160 SPI Clock Frequency Config

Carl Richard — Mon, 26 Jul 2021 07:49:47 GMT

Hello, NIkhil!

Thanks for reaching out. To make it easier for me to help you please provide some more details:

- What kind of faults are you getting?

- How is your CS configured? If you control it manually you could try the approach described in this thread.

Best regards,
Carl Richard