NRF5340 TWIM example code to communicate with nPM1300

RE: NRF5340 TWIM example code to communicate with nPM1300

Susheel Nuguru — Tue, 10 Sep 2024 09:57:47 GMT

[quote user="Bas van den Berg"]What I could find is that Zephyr didn't seem to use TXRX..[/quote]

Yes, That seems true. Need to understand the code architecture to see how this is working in Zephyr.

[quote user="Bas van den Berg"]Also I think the primary length should be 2 bytes, since the address is passed separately right?[/quote]

Yup, you are right, my bad.

RE: NRF5340 TWIM example code to communicate with nPM1300

Bas van den Berg — Tue, 10 Sep 2024 08:47:57 GMT

I assume the nPM1300 works fine under Zephyr. Inside the Zephyr codebase the code seems spread out over an nPM1300 driver and an i2c driver. What I could find is that Zephyr didn't seem to use TXRX..

Also I think the primary length should be 2 bytes, since the address is passed separately right?

RE: NRF5340 TWIM example code to communicate with nPM1300

Susheel Nuguru — Tue, 10 Sep 2024 08:08:23 GMT

We do not support FreeRTOS on nRF53 officially and I did not had time to experiment with it as we went all in with Zephyr RTOS.

But your question does not seem to be very specifically tied to the FreeRTOS.

To perform a read operation as described in the nPM specification, you would need to set up a TXRX transfer. This involves a write operation (to send the 7-bit device address and 16-bit register address) followed by a read operation (to read 8 bits).Maybe you should do something like this, haven't tested this myself so use for template only.

nrfx_twim_xfer_desc_t xfer_desc;
xfer_desc.type = NRFX_TWIM_XFER_TXRX;
xfer_desc.address = device_address;
xfer_desc.primary_length = 3; // 7-bit device address + 16-bit register address
xfer_desc.secondary_length = 1; // 8 bits to read
xfer_desc.p_primary_buf = &write_buffer; // Buffer containing device and register addresses
xfer_desc.p_secondary_buf = &read_buffer; // Buffer to store read data

nrfx_err_t err_code = nrfx_twim_xfer(&twim_instance, &xfer_desc, flags);

RE: NRF5340 TWIM example code to communicate with nPM1300

Bas van den Berg — Mon, 09 Sep 2024 13:13:25 GMT

We are running FreeRTOS.

So the twim_master.h basicallly contains one transfer function (nrfx_twim_xfer).

Looking at 7.6 TWI in the nPM specification, i see a read is comprised of:

- sending 7-bit device address (+r/w bit)

- sending 16 bit register address

- reading 8 bits.

How can i do this with the xfer function?

Regards,

Bas

RE: NRF5340 TWIM example code to communicate with nPM1300

runsiv — Mon, 09 Sep 2024 11:27:31 GMT

Hi Bas

Just out of curiosity, what do you plan to run on the nRF5340 as you are not using Zephyr?

As you mention the NPMX I presume you have looked into the Working with nPM1300 in other SDKs?

i just need to understand the your goal when I talk with the PMIC team

Regards

Runar