SAADC always busy

[dblasco]

Hi!

I am working with PCA10040 (nRF52), s132 and SDK 12.2.0.

I am using the example experimental_ble_app_eddystone. I have configured one slot as TLM, so it reports battery (value should be refreshed every 30 advertisments).

However, the battery is measured just once at the beginning, the rest of the times nrf_drv_saadc_is_busy() will return true. If voltage changes, the initial value remains unchanged.

I have changed SAADC_CONFIG_LP_MODE to enable low power mode (it drains continuously about 2mA without doing so). However, putting this back to normal mode does not help.

Could anyone tell me if I am doing something wrong, or could this be caused by a bug in the example?

Thank you

[Jørgen Holmefjord]

Hi,

There are some issues with low-power mode in SDK 12.x. These should be fixed in SDK 13. Where do the sampling stop? Do you get an error code from any calls to driver functions?

Are you using double buffering in your application? The SAADC will be kept in the busy-state as long as there are a second buffer setup for sampling. This is also causing some issues for users trying to run the calibration task, as described in this post.

Best regards,

Jørgen

[dblasco]

Hi Jørgen. I have updated SAADC driver and the part related to the battery measurement of eddystone example to SDK13. It works now (however, the whole eddystone example in SDK 13 does not work, gives an error in ble_stack_init, in case you wanted to check). Thank you for your help. I

[Jørgen Holmefjord]

Great that you got it working! Which error do you get from ble_stack_init? Have you flashed the correct softdevice? Have you made any other changes to the SDK? I tried the Eddystone example from SDK 13 on my board, and it seems to work as expected.

[dblasco]

I got error 0x3001 in sd_ble_cfg_set. I have not made any modification to this SDK 13.0.0 (downloaded yesterday) Softdevice used was s132 v3.0.1 (the same as with SDK12). Maybe should I have used 4.0.2?

[Jørgen Holmefjord]

Yes, you need to use one of the supported softdevices. From release notes:

Supported SoftDevices:

• S132 v4.0.2
• S140 v5.0.0-2.alpha
• S212 v4.0.0