RE: TWI: change SCL and SDA directly?

Ladasky — Mon, 09 May 2016 22:25:20 GMT

Hello again RK, you seem to respond to most of my questions. Thanks for your help.

I consulted Sections 18 (GPIO) and 47 (TWI) of the nRF52832 hardware specification. Section 47.2 mentions two registers, PSELSCL and PSELSDA, which are associated with connecting the TWI to GPIO. When you write, "write 0xffffffff to the two pin registers to disconnect them," are these the two registers you meant? I guess I would read the contents of these registers, store their values, then overwrite with 0xFFFFFFFF, then perform my sleep-and-wake procedure, and finally restore the register values.

Alternately, I guess I could also call nrf_drv_twi_uninit(). Shouldn't that release the GPIO lines from TWI hardware control? Next, I would perform my sleep-and-wake procedure, then call nrf_drv_twi_init(). Is that a better or worse procedure than the above?

RE: TWI: change SCL and SDA directly?

RK — Sat, 07 May 2016 01:13:35 GMT

Just wait until the TWI is finished, write 0xffffffff to the two pin registers to disconnect them, write the GPIO pins yourself with a simple delay to generate the reset you want, then put the pins back in the registers again. No need to be fancy about it.