RE: nRF53840 SPI1 maximum clock rate?

Dave Littell — Fri, 12 Dec 2025 14:17:34 GMT

Very good, thanks!

RE: nRF53840 SPI1 maximum clock rate?

Syed Maysum Abbas Zaidi — Fri, 12 Dec 2025 12:59:25 GMT

Hi,

On the nRF52840, not all SPI instances support a 32 MHz clock. There are two different SPI peripherals:

SPI (legacy SPI, no EasyDMA): maximum 8 MHz
SPIM (SPI master with EasyDMA)
1. SPIM0 / SPIM1 / SPIM2: maximum 8 MHz
2. SPIM3 only: supports up to 32 MHz

So. If your device is bound to a legacy SPI peripheral, it will always be limited to 8 MHz, regardless of the DTS value. Moreover if in your DTS it is using SPIM0/SPIM1/SPIM2, it will still be limited to 8 MHz. Only SPIM3 supports 32 MHz, so to use 32 MHz the device must be connected to SPIM3, and that instance must be enabled in the devicetree. You can verify this by checking your DTS / overlay and the final generated devicetree (build/zephyr/zephyr.dts) to see which hardware block your SPI node is actually mapped to.

Best Regards,
Syed Maysum