52832 about the external 32mhz crystal

[victor_CHINA]

Dear nordic employee

My 52832’s GPIO control the external 32mhz crystal‘s power，

when the 52832 work in the sleepmode ,I cut the 32mhz crystal'power

then when I want to turn on the crystal's power by a gpio or spi, does it work?

Can spi or gpio work well without the external 32mhz crystal？

or should I turn the HCLK source to the internal 32 mhz crystal before I use the gpio or SPI？ , what should I do?

I think SPI's clock source is the 32MHZ，right?

but what the clock source of the GPIO?     

best regards!

victor

[FormerMember]

Yes, it will work fine to use SPI  with the internal 64 MHz oscillator (HFINT). HFINT will be used as long as the external crystal is not explicitly started, i.e. as long as you don't set TASKS_HFCLKSTART to '1'. You can read about it in the "HFCLK clock controller" section in the product specification. 

What do you mean by clock source of the GPIO?

[victor_CHINA]

Hi Kristin

Thanks for your reply.

My question：

1、now I know HFINT will be used as long as the external crystal is not explicitly started

but if  set TASKS_HFCLKSTART  to '0'，does that mean I close all the HCLK？ I have closed not only the external crystal but also the internal 64mhz？

1、I know the HFCLK clock controller provide the clock for SPI ,  but what the clock source of GPIO?

Does the HFCLK provide the clock for GPIO？

2、Now I use a TCXO（temperature compensated crystal oscillator） for NRF52832 and another RF IC

Because the TCXO‘s current is high， so when the TCXO provide the clock signal for the 52832，I must control the TCXO'power（EG：when the bluetooth  radio is working，I turn on the TCXO，when the bluetooth radio is not working ，I turn off the TCXO）

But I have not find the way to control the TCXO according to the bluetooth radio work state（because I donot know the SoftDevice's detail）

Can you tell me?

the TCXO:

Best regards

victor

[FormerMember]

1. A GPIO is a pin that can be toggled, it doesn't have a clock source associated with it.
2. The nRF52832 doesn't support external clock signal and it needs to have a crystal. It was possible on the nRF51, but the clock module is redesigned and external 32MHz clocks is not a feature of nRF52. You can try at your own discretion, but the nRF52 is so sensitive to jitter and noise that Nordic will not make any guarantees. A crystal is needed to ensure performance.
   
   Using Radio Notifications, the softdevice informs when the softdevice will use the radio.