Zephyr TWIM too slow so need to use NRFX driver

RE: Zephyr TWIM too slow so need to use NRFX driver

Nissanth — Mon, 14 Sep 2026 15:04:56 GMT

Hi,

That happends, because when you hand the driver two seperate i2c_msg fragments, it sends each one as its own transfer and holds SCL low in between while the CPU catches up.

If both is a write operation, you can try to put the bytes in one buffer and do a single i2c_write(). One transfer without a gap.

If you attempt to do a write then read operation, you can either add compatible = "nordic,nrf-twi"; in your boards overlay files, or go to nrfx and use NRFX_TWIM_XFER_TXRX. This does a write then read as a single hardware transfer.

are you doing two write operation or write then read?

Regards,

Nissanth Karunanithy

RE: Zephyr TWIM too slow so need to use NRFX driver

John Galvin — Mon, 14 Sep 2026 10:00:19 GMT

Just an udate. I've tried building the blocking & ono-blocking examples for the NRF52DK/52832.

Firstly neither would build for 3.4.0 & I have to edit the overlay files to change "

#include "../../../common/common-pinctrl.dtsi" to " #include "../common/common-pinctrl.dtsi"

In file included from <command-line>:
C:/Work/tx_rx_blocking_1/boards/nrf52dk_nrf52832.overlay:1:10: fatal error: ../../../common/common-pinctrl.dtsi: No such file or directory

Working on the blocking sample

Once built & connected 0.3 to 0.4 & 0.30 to 0.31

I then step thru (or run) and it hangs at

status = nrfx_twim_xfer(&twim_inst, &twim_xfer_desc, 0); (line 118)