Cannot get 400 kbps TWI_SW frequancy with clock stretching

[chinargor]

Hi Nordic developers,

I'm using TWI software driver provided by NORDIC. I need to have 400 kbps frequancy. I have seted TWI_DELAY() to 0 and TWI_MASTER_TIMEOUT_COUNTER_LOAD_VALUE to 1000. (for clock stretching)

Just checking with osciloscope SCL clock period is 3us instead of 2.5us.

When I set the TWI_MASTER_TIMEOUT_COUNTER_LOAD_VALUE to 0 I'm getting exactly 2.5 us.

How can I get 2.5 us SCL clock cycle with clock stretching?

I'd be really glad, if someone can help me.

Thanks in advance,

Gor

[chinargor]

Hi,

Thanks a lot for your help. Actually for some reasons I'm using twi_hw_master library (not nrf_drv_twi). But your idea is interesting and can also be implemented in twi_hw_master. Thanks again

[MartinBL]

No problem. The driver was completely redesigned in SDK 8.1.0. The SDK team strives to design new drivers that is compatible with both nRF51 and the new 52. So it is hard to keep up with all the new releases.