the connection of SAADC

RE: the connection of SAADC

haakonsh — Thu, 05 Apr 2018 12:52:02 GMT

No problem Kiyoshi.

FYI you can calibrate the offset with a call to nrf_drv_saadc_calibrate_offset.

Cheers,
Håkon

RE: the connection of SAADC

Kiyoshi Iwai — Thu, 05 Apr 2018 02:00:30 GMT

Hello Håkon,

Thank you for rapid reply.

I already know the way of single-end.

I just want to measure the DC offset of SAADC and to cancel the error,

but after re-considering, it's impossible to know the offset, I understood.

Sorry for strange question.

Thanks,

Kiyoshi Iwai

RE: the connection of SAADC

haakonsh — Wed, 04 Apr 2018 13:55:36 GMT

Hey Kiyoshi,

"measure the voltage of GND?" I'm not quite sure what you mean.

To set the negative input of a channel to GND you must initialize a channel by calling nrf_drv_saadc_channel_init() with a nrf_saadc_channel_config_t where the mode set to nrf_saadc_mode_t NRF_SAADC_MODE_SINGLE_ENDED. Then the negative input will be connected to GND internally. You will still need some other voltage reference connected to the positive input.

Cheers,

Håkon.