TWI stuck and blocked

RE: TWI stuck and blocked

MartinBL — Fri, 15 Jul 2016 14:46:16 GMT

Ouch! Sorry to hear that. Glad it's solved though.

RE: TWI stuck and blocked

Chris — Fri, 15 Jul 2016 11:28:36 GMT

Manufacturer had chip on backwards..

RE: TWI stuck and blocked

Chris — Mon, 23 May 2016 13:32:19 GMT

Thanks Martin, will update once I debug.

RE: TWI stuck and blocked

MartinBL — Mon, 23 May 2016 13:30:50 GMT

Sounds good. I'll wait for an update with a logic trace then.

RE: TWI stuck and blocked

Chris — Mon, 23 May 2016 13:05:44 GMT

It's a nice part, its got some crazy range for a capacitive prox pickup... best out of about 5 chips I tried.

Plus works across the V range of the Nordic.. so its a nice tidy combo.

RE: TWI stuck and blocked

Chris — Mon, 23 May 2016 13:05:13 GMT

I looked at the driver you sent (I had another one from the chip co) and it's doing what I'm doing.. so I think its a HW fault on my boards. They are new (Board bring up) but simple but hey.. never know.

Might have to wait until I can get the scope/logic analyser on it.. give me a chance to try my new analyser!!

And yeah, the docs say to do it that way.. I don't think the line ever moves from ground which makes me wonder if the chip is powered/working at all.. I don't even have a multi-meter with me which is a pain.

RE: TWI stuck and blocked

MartinBL — Mon, 23 May 2016 13:03:03 GMT

Does it say anywhere that you should take control of the RDY pin like this?

Maybe you can try to use a TWI event handler and see if it returns any error codes that make sense.

Anyway I think a logic trace might be very helpful.

RE: TWI stuck and blocked

Chris — Mon, 23 May 2016 11:50:44 GMT

Hi Martin,

Yes, I also went and re-read the driver code as well as their data sheet (I had made some assumptions) but it doesn't appear to have fix it.

For example I now do this to wait for the communications window with the IC but it appears to break after no delay (which I find almost impossible to believe)..

So I had set it as an input with a pull-up so it sits high..

Then I pull it low for 10ms to signal to the IQS that I want to communicate

Then I set it as an input (floating high) and the IQS should pull it low to say "ok, I'm ready"

But doesn't seem to happen.

I'm in Sweden at the mo so will have to wait until I get back to NZ to break out the scope and figure out what's up.. feel its a HW problem on my PCB..

nrf_gpio_cfg_input(PROXIMITY_I2C_RDY, NRF_GPIO_PIN_PULLUP);
delay_ms(10);

// We need to pull the RDY line low for at least 10ms
nrf_gpio_cfg_output(PROXIMITY_I2C_RDY);
nrf_gpio_pin_clear(PROXIMITY_I2C_RDY);

delay_ms(10);

nrf_gpio_cfg_input(PROXIMITY_I2C_RDY, NRF_GPIO_PIN_PULLUP);


int i=0;
for (i=0; i<200; i++) {
    if (!nrf_gpio_pin_read(PROXIMITY_I2C_RDY)) {
        break;
    }
    delay_ms(1);
}

if (i == 200) {
    RMLOG("Broke out, never detected");
}
RMLOG("Detected after %u",i);

RE: TWI stuck and blocked

MartinBL — Mon, 23 May 2016 10:20:08 GMT

Hi,

If I understand you correctly you are using a GPIO on the nRF52 to pull down the RDY pin whenever you want to read data. However the way I read the datasheet, and after skimming through this IQS263 driver, that is not the way to go. I think the IQS263 is controlling the pin, pulling it low whenever it has new data available. What you should do is to set up an interrupt triggering on a negative edge on the RDY signal. When the interrupt is triggered you can read data.

I think the datasheet is a little vague on this though, so I might be wrong.