Interrupt priority each 100us

RE: Interrupt priority each 100us

RK — Fri, 21 Jul 2017 08:59:17 GMT

yes it will be delayed for up to many ms depending on whether you're in connection and how many connections. The softdevice spec should give the max time you'll be blocked, but it would take some wading through.

You cannot do precision interrupt-based timing operations with the softdevice running.

RE: Interrupt priority each 100us

Milena — Fri, 21 Jul 2017 08:46:11 GMT

Thanks for your answer. To be clear, we plan to the PWM module. But we need to change the duty cycle every 100us (following a lookup table). Seems that if a BLE IRQ comes at this moment, the PWM duty cycle change will be delayed. Right?

RE: Interrupt priority each 100us

RK — Fri, 21 Jul 2017 08:28:03 GMT

the timings are all in the softdevice spec, although they seem harder to decipher than they used to be. Either way - people keep trying to do PWM with interrupts and it never works. Please use the search feature and read some of the hundreds of questions about PWM, PWM with interrupts, PWM with the softdevice and any other variation. You need to use the hardware PWM peripheral or another non-interrupt based solution.

RE: Interrupt priority each 100us

Milena — Fri, 21 Jul 2017 08:22:10 GMT

Ok, I put transitors! Thanks.

For my application I have to make a driver motor brushless. I have three coil and each 100us I have to change the coil and the PWM.

I will test with my EVM the precision of my interrupts of 100us. Do you know the critical tasks how long is it ?

RE: Interrupt priority each 100us

RK — Fri, 21 Jul 2017 08:10:41 GMT

You need a transistor - this is in the datasheet somewhere - look for paragraphs about high and low drive strength and the max number of pins you can use with high enabled. It's a lot less than 60mA
If you are doing PWM then instead of trying to do it with interrupts, which isn't going to work very well, how about using the PWM module on the chip.

RE: Interrupt priority each 100us

Milena — Fri, 21 Jul 2017 07:41:35 GMT

Ok, I put transitors! Thanks.

For my application I have to make a driver motor brushless. I have three coil and each 100us I have to change the coil and the PWM.

I will test with my EVM the precision of my interrupts of 100us. Do you know the critical tasks how long is it ?

RE: Interrupt priority each 100us

Jørgen Holmefjord — Fri, 21 Jul 2017 07:26:19 GMT

Hi Milena,

It is not possible to give the application priority over BLE. The softdevice have the highest priority level reserved for timing critical tasks. You can see the interrupt priority levels in the S132 softdevice specifications.

The current will vary with chip type and configuration. Which chip are you looking into? What current are you asking about? Current consumption or something else?

Best regards,

Jørgen