Disable interrupts

[gaminn]

Hi, I want to do this cycle with GPIO without interrupting it on NRF51 with BLE softdevice:

1. PIN1 to HIGH level
2. read value of PIN2
3. PIN1 to LOW level

Repeat this 25 times (between cycles interrupts can happen)

What is the easiest way to accomplish that?

[Susheel Nuguru]

Im little confused with the title and the contents of the question. Are you asking if you can read PIN2 everytime PIN1 have a transition to high level for 25 cycles without enabling GPIO interrupt?

[gaminn]

I apologize. I want to execute steps 1) to 3) without being interrupted by any interrupt (user interrupt or softdevice interrupt), because I have to keep strict timing of the peripheral which is connected to the GPIO (PIN1 HIGH level can't last more than 60 us in no way).

[Susheel Nuguru]

the softdevice will allow blocking its interrupts for <=10us. But 60us is too much and the softdevice may assert if you try to block its interrupts for so long.

[gaminn]

The whole cycle will last <=6 us. So is it really possible to disable interrupts for <=10 us by __disable_irq();? Because there was a post on this forum (I can't remember the link) stating that disabling softdevice interrupts for arbitrary time period will eventually break timing in softdevice.

[Susheel Nuguru]

We strongly recommend not to disable global interrupts (and hence softdevice interrupts) but if you do not have any option then disabling it for <=10us should work.