how to read data from slave via TWI

RE: how to read data from slave via TWI

awneil — Mon, 15 Jul 2019 12:29:12 GMT

[quote userid="81289" url="~/f/nordic-q-a/49702/how-to-read-data-from-slave-via-twi/198445"]How to put buffer in RAM[/quote]

By default, it will be.

The point is not to try to put it anywhere other than RAM.

RE: how to read data from slave via TWI

awneil — Mon, 15 Jul 2019 12:28:11 GMT

[quote userid="81289" url="~/f/nordic-q-a/49702/how-to-read-data-from-slave-via-twi/198445"]Any code examples on how to communicate between 2 nRF52 devices[/quote]

Again, as said in your previous thread, the way to approach this is not to try to do both ends at once!

Start by getting your Master thoroughly working, debugged, and instrumented with a standard Slave.

Then you can move onto your own slave.

RE: how to read data from slave via TWI

Anisa — Mon, 15 Jul 2019 12:11:26 GMT

Hi Simon,

Thanks for the reply. So the state of slave device (nrf52) must be checked with (NRFX_TWIS_SUBSTATE_IDLE, and when state is idle them Master (nrf52) sends the buffer using nrf_drv_twi_tx to slave. Slave fills this buffer with data. Master again reads it via nrf_drv_twi_rx().

Is above understanding correct? Any code examples on how to communicate between 2 nRF52 devices?

SDK documentation says:

Note:Peripherals using EasyDMA (including TWIS) require the transfer buffers to be placed in the Data RAM region. If this condition is not met, this function will fail with the error code NRFX_ERROR_INVALID_ADDR.

How to put buffer in RAM?

RE: how to read data from slave via TWI

Simonr — Mon, 15 Jul 2019 09:35:30 GMT

Hi Anisa

You can see that the TWIS_EVT_READ_REQ and WRITE_REQ functions are called in nrfx_twis.c when the TWI peripheral is idle (NRFX_TWIS_SUBSTATE_IDLE). For more details please check your SDK. in this path ....\modules\nrfx\drivers\src\nrfx_twis.c

Due to the summer holidays in Norway, our support team is understaffed this week, and delayed replies must be expected. Sorry for the inconvenience!

Best regards,

Simon

RE: how to read data from slave via TWI

awneil — Fri, 12 Jul 2019 13:37:31 GMT

We've been through all this before.

See my reply in your original thread:

https://devzone.nordicsemi.com/f/nordic-q-a/49316/twi-communication-between-two-nrf52-device/196292#196292

RE: how to read data from slave via TWI

Anisa — Fri, 12 Jul 2019 12:59:12 GMT

Can you tell me how TWIS_EVT_READ_REQ event and TWIS_EVT_WRITE_REQ is called? Does master calls it?

Nordic SDK documentation is not clear.

RE: how to read data from slave via TWI

awneil — Fri, 12 Jul 2019 10:56:21 GMT

So what does this have to do with TWI?

Your question doesn't make sense!

RE: how to read data from slave via TWI

Anisa — Fri, 12 Jul 2019 10:48:11 GMT

yes, Connection between master and slave works and slave device is detected as well. Now trying to use GPIOTE pin handler.

RE: how to read data from slave via TWI

awneil — Fri, 12 Jul 2019 10:44:20 GMT

So are you still trying to connect two nRF52s together via I2C - one nRF52 as a Master, the other nRF52 as a Slave?

https://devzone.nordicsemi.com/f/nordic-q-a/49316/twi-communication-between-two-nrf52-device