high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

alonmat — Thu, 30 Dec 2021 12:59:40 GMT

the following steps solved the problem:

1) Removing the pullup resitors for SCL and SDO

and

2) writing 90h to the accelrometer register 1Eh (canceling the SDO internal pullup)

Thnaks for helpful assitance 🙂

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

alonmat — Thu, 30 Dec 2021 07:50:20 GMT

We are trying to check it without pullup resistors on SPI lines

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

Hung Bui — Tue, 28 Dec 2021 14:34:50 GMT

I understand, but the problem is lying on the pullups you are using for the I2C it's where it's drawing current when you switch to SPI.

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

alonmat — Tue, 28 Dec 2021 09:41:40 GMT

in I2C, we doesn't have any problems. when no transfer of data, there is no currrent consumptiomn.

the problem is only in SPI.

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

Hung Bui — Tue, 28 Dec 2021 09:38:01 GMT

Hi Alon,

The errata is applied only for some built code and the workaround is usually implemented already in the SDK. So most likely it's not the issue.

In your case it seems the pullups is causing the trouble ?
Is it possible to remove the pullups and use the internal pullup on the pin when you are communicate via I2C ?
On SPI you don't need to use pullups.

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

alonmat — Tue, 28 Dec 2021 08:32:20 GMT

1) SPI driver is implemented on version 1.6.4 and works with DMA

2) SPI consume a lot of current, even if it not actually transfer data :

- the other SPI to flash doesn't consume current if no data is transfered.

- even if only initializing the SPI using nrfx_spim_init cause the current consumption to increase significantly

- it seems the driver init function assert the CLK, MISO and MOSI to ground and this cause

- changing the SPI mode clock to mode 3 - change the CLK default to high

- changing NRFX_SPIM_MISO_PULL_CFG to 0 - changed the default MISO to high

- MOSI is set to ground and I think this cause a problem.

- calling nrfx_spim_uninit reduce the current but not all of the current before the SPI initialized

- also setting all SPI to input with PULLUP reduce the current but not all of the current before the SPI initialized

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

alonmat — Tue, 28 Dec 2021 08:18:12 GMT

about the errata.

we are using SPIM2 and we have configured interrupts on INT1 and INT2 of the accelerometer to the nordic cpu.

do you think is it applied to my case ?

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

alonmat — Tue, 28 Dec 2021 08:15:50 GMT

We are using Pullup in the SPI signals

RE: high current consumption when we are using Accelerometer lis3dh with SPI with no transfer at all on SPI

Hung Bui — Mon, 27 Dec 2021 16:13:14 GMT

Hi Alon,

Do you use any pull up resistors in your SPI wire connections ?

Can you share the schematic on how you connect I2C and SPI to the chip ?

Also have you check if this errata is applied for you ?