How to reduce Gazell disable current

[Joe]

When I call nrf_gzll_enable(), then nrf_gzll_disable(), and go to sleep with __WFE(), there is about extra 6uA draw due to this enable/disable action. It seems the nrf_gzll_disable() does not turn everything off due to the use of the radio. How can I eliminate this 6uA draw, if possible.

Thanks.

[ovrebekk]

Hi Joe

It sounds like you have run into errata issue 78, which affects the timers in the nRF52832. Unless they are shutdown using the SHUTDOWN task, they will draw excessive current in system ON sleep mode.

Could you try to shut down the timer manually after disabling Gazell, before entering sleep, and see if it solves the issue?

To shut down the timer simply activate the SHUTDOWN task like this:

NRF_TIMER0->TASKS_SHUTDOWN = 1;

Or like this, if you use the SoftDevice compliant version of Gazell:

NRF_TIMER2->TASKS_SHUTDOWN = 1;

Best regards
Torbjørn

[Joe]

Hi Torbjorn,

I used the Timer0 shutdown, it has indeed removed the 6 uA current while it is disabled. However, I have trouble in re-enabling the radio back later. Is there timing requirement between the SHUTDOWN and sleep? Is there additional thing to do for nrf_gzll_enable() to start up the radio after the SHUTDOWN?

Thanks.

Joseph

[Joe]

I think I figured it out. If I wait for the radio to be completely disabled, then shutdown the timer. The next wakeup and transmission will be successful. Thanks.

[ovrebekk]

Hi Joe

It's good to hear you figured it out :)

Best regards