Trying To Drive IMU via GPIO

RE: Trying To Drive IMU via GPIO

ahmdm — Wed, 12 Dec 2018 05:00:43 GMT

I wanted to turn it on only when i needed it in order to save battery. neverthless, I guess I'll use a mosfet to control it's power. that seems to me a more feasible solution.

Thanks for your support. I really appreciate it.

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Tue, 11 Dec 2018 13:00:05 GMT

The specifications give a range from 6 mA (min) to 14 mA (max) with a typical value of 9 mA. It could be that the chip is not able to source 9 mA drawn by the IMU.

I_OH,HDH

Current at VDD-0.4 V, output set high, high drive, VDD >= 2.7 V

Is there any reason that you can't power the IMU directly from VDD?

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Tue, 11 Dec 2018 13:00:04 GMT

The specifications give a range from 6 mA (min) to 14 mA (max) with a typical value of 9 mA. It could be that the chip is not able to source 9 mA drawn by the IMU.

I_OH,HDH

Current at VDD-0.4 V, output set high, high drive, VDD >= 2.7 V

Is there any reason that you can't power the IMU directly from VDD?

RE: Trying To Drive IMU via GPIO

ahmdm — Tue, 11 Dec 2018 10:33:09 GMT

I tested the current and it draws 9mA max.

I tested pin 13 same result.

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Tue, 11 Dec 2018 10:26:28 GMT

How much current does the IMU draw? The GPIOs should be able to sink/source up to 15 mA in high drive mode. Have you tried other GPIOs than P0.10?

RE: Trying To Drive IMU via GPIO

ahmdm — Tue, 11 Dec 2018 08:46:06 GMT

Okay so the thing is that I am now trying it on my nrf52DK pca10040. I have shorted the r27/r28 resistors. The situation is that as soon as I turn it on the led on the IMU,keeps toggling. Is it that the GPIO is not supplying enough current or some other issue?

RE: Trying To Drive IMU via GPIO

ahmdm — Tue, 11 Dec 2018 04:30:17 GMT

It is returning 0x1000120C: FFFFFFFE

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Mon, 10 Dec 2018 13:26:44 GMT

Just to be sure, can you read the UICR register using nrfjprog (nrfjprog --memrd 0x1000120c)? This should return 0x1000120C: FFFFFFFE if the GPIOs are correctly configured.

RE: Trying To Drive IMU via GPIO

ahmdm — Mon, 10 Dec 2018 13:05:05 GMT

Defined it in both.

Although I am suspecting the ic might not be soldered properly. Bot sure though still .

Any thing else I could check?

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Mon, 10 Dec 2018 12:12:25 GMT

Did you only define it in Asm, or C/C++ tab as well? The config is applied in system_nrf52.c. If it is only defined in Asm, the change will not take effect.

RE: Trying To Drive IMU via GPIO

ahmdm — Mon, 10 Dec 2018 10:51:24 GMT

I have defined it like this

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Mon, 10 Dec 2018 08:59:34 GMT

Where did you define CONFIG_NFCT_PINS_AS_GPIOS? This should be configured in the project's preprocessor symbols to be affective.

RE: Trying To Drive IMU via GPIO

ahmdm — Mon, 10 Dec 2018 07:19:18 GMT

I have tested the following:

tested other gpio pins that are not NFCT pins and they are working as programmed.

Tested pins 9 and 10 and they are giving me a voltages from 0-0.4V when set without the IMU connected

I don't understand what might be the issue here.

RE: Trying To Drive IMU via GPIO

ahmdm — Sat, 08 Dec 2018 12:46:13 GMT

I'll test all this l, try to narrow it down and get back to you .

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Fri, 07 Dec 2018 14:39:32 GMT

What is the pin voltage if you have not connected the IMU? Are you able to control the GPIO from your code (set it high/low) if there is nothing connected? Have you tried other pins that is not used for other peripherals (like the NFCT antenna)?

RE: Trying To Drive IMU via GPIO

ahmdm — Fri, 07 Dec 2018 10:34:47 GMT

yes I am testing it on a custom board. The board is powered via a 3.3v regulator (AP2112k) that is connected to a LiPo battery.

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Fri, 07 Dec 2018 10:03:58 GMT

[quote user="ahmedm"]I plan to drive it on a custom board[/quote]

Are you testing it on a custom board now? What is the supply voltage of the board you are connecting the IMU to?

RE: Trying To Drive IMU via GPIO

ahmdm — Fri, 07 Dec 2018 09:51:31 GMT

Yes .I want to drive the Vdd of the IMU . Required VOLTAGE IS 3.3V

I plan to drive it on a custom board . When I check with a meter it's alternating between 0 and around 0.45V

RE: Trying To Drive IMU via GPIO

Jørgen Holmefjord — Fri, 07 Dec 2018 09:43:29 GMT

Hi,

Do you mean that you want to drive VDD of the IMU from the GPIO?

What is the supply voltage?
Is this on a nRF52-DK or on a custom board?
What is the voltage of the pin if it is not connected to the IMU?

Best regards,
Jørgen