interrupt based i2c with softdevice

RE: interrupt based i2c with softdevice

MartinBL — Tue, 27 Oct 2015 09:50:08 GMT

@Brian: Let us continue this case here: TWI in Low power.

RE: interrupt based i2c with softdevice

Brian — Tue, 27 Oct 2015 00:30:22 GMT

Is this the correct way to be using the driver in non-blocking mode? Trying to achieve the lowest possible power. The event handler gets called, but it doesn't appear to wake up from WFE or power_manage if running with BLE. Thanks! Brian

 nrf_drv_twi_init(&p_twi_instance, &p_twi_config, twi_event_handler); 
  nrf_drv_twi_enable(&p_twi_instance); // Enable the TWI instance   

while(1) {

    nrf_drv_twi_rx(&p_twi_instance, 0x55, dummy_data, 7, false);          
    //power_manage()                                      
    __WFE();   
}

static void twi_event_handler(nrf_drv_twi_evt_t *p_evt){   
    if(p_evt->type == NRF_DRV_TWI_RX_DONE)
    {

      SEGGER_RTT_printf(0, "\n\nDATA: ", dummy_data);
      for(i=0;i<7;i++) SEGGER_RTT_printf(0, "%02x ", dummy_data[i]);

    } 
}

RE: interrupt based i2c with softdevice

sowmya — Mon, 12 Oct 2015 07:44:51 GMT

Yes, we can use event_handler for I2C. Thank you for the relpy. I tested the both drivers given with SDK and my custom driver(interrupt based , no event handler). Thank you for the support Martin.

RE: interrupt based i2c with softdevice

MartinBL — Mon, 12 Oct 2015 07:41:49 GMT

The TWI driver in SDK 9.0.0 can actually be used in both blocking and interrupt driven mode. Just pass an event handler to nrf_drv_twi_init(p_instance, p_config , event_handler);. However, I'm sure you can make a more efficient, interrupt driven TWI driver yourself.

RE: interrupt based i2c with softdevice

sowmya — Sat, 10 Oct 2015 05:05:40 GMT

Hi, I tested the eeprom using the i2c driver provided with sdk. But I wanted the interrupt based and not to use state machine based which is using in twi driver. So I wrote my own driver and interrupt based and it is working without PPI or softdevice calls. Thank you for the reply regarding PPI usage in twi driver.

RE: interrupt based i2c with softdevice

MartinBL — Fri, 09 Oct 2015 12:56:37 GMT

Hi. Sorry for the late response. Torbjørn's example is based on an old TWI driver. The use of PPI channels is a legacy from revision 2 of the nRF51 which had a product anomaly causing the TWI to malfunction (the anomaly is documented in PAN V2.3). The workaround was to use PPI channels. To make it even more complicated the TWI and softdevice would sometimes fight over the same PPI channels, and that is why you see specialized softdevice calls in Torbjørn's TWI driver to handle proper delegation of PPI channels.

Nowadays, however, if you use the latest 3rd revision nRF51, the PAN is fixed and you don't need to use the PPI channels at all. I realize it might be a little late to say now, but in SDK 9 there is a brand new TWI driver and I would highly recommend that you use this driver instead of the old one found in your example.

RE: interrupt based i2c with softdevice

sowmya — Thu, 01 Oct 2015 06:15:37 GMT

The issue is fixed. We have to first initialise softdevice then initialise I2C. One more question is , is it mandatory to use PPI or soft device calls in i2c?

My application is running without PPI or softdevice calls. I am using NVIC to enable interrupts.

RE: interrupt based i2c with softdevice

sowmya — Thu, 01 Oct 2015 05:22:47 GMT

Hello I re-checked and still I2C is not working with softdevice. Anyone can help to fix this?

RE: interrupt based i2c with softdevice

sowmya — Wed, 30 Sep 2015 13:01:50 GMT

I have done 2 tests:

I2C with template application : I2C working, BT not working.
I2C with HRS application : I2C and BT not working.

RE: interrupt based i2c with softdevice

sowmya — Wed, 30 Sep 2015 13:00:48 GMT

I tested heart rate application without I2C and changed the clock source, and it is working. But after integrating i2c driver in main.c of hrs application, code is getting hardfault .

RE: interrupt based i2c with softdevice

MartinBL — Wed, 30 Sep 2015 12:54:38 GMT

So you are all good or are you still stuck somewhere?

RE: interrupt based i2c with softdevice

sowmya — Wed, 30 Sep 2015 12:39:13 GMT

For BLE advertise I am using the same main.c file provided by nordic to initialise stack and SDK but it was not advertising and was hanged in SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, NULL);

Now I changed the source to NRF_CLOCK_LFCLKSRC_RC_250_PPM_8000MS_CALIBRATION, it is working.

As I am doing some tests on the BT stack, it was working with clock source NRF_CLOCK_LFCLKSRC_XTAL_20_PPM.

RE: interrupt based i2c with softdevice

MartinBL — Wed, 30 Sep 2015 12:34:51 GMT

Do you mind uploading your main.c file and/or other relevant code?