Events and Tasks, any peripherals designed like the Nordic nrf52 series? - Page 1
Forum section: electronics / general

author: jnz
author_rank: Frequent Contributor
timestamp: February 06, 2018, 07:09:16 am
content: I won’t get too much into the details but while reading about the Nordic nrf52832 I thought it was a little odd each peripheral had tasks like START STOP ETC tasks and DONE BUSY CLEAR RX/TXDATA ETC events - where a 0 or 1 inside a 32bit register for example would start a peripheral and a separate 32bit would stop it, and the same with flags/events.Then I read their PPI system - where you can “connect” one peripheral’s event to another’s task without CPU intervention. So for example you could create a link from Timer1 rollover to GPIO C2 low and SPI transmit some number of bytes out of DMA all in theory without the CPU doing anything.While I don’t have any specific uses for this yet - it seems pretty cool. All of their peripherals were designed from inception to work with this task and event system.Are there any other common micros with a system like this? Just wondering how unique this is to Nordic.And if anyone has used this, does it work well?

author: ataradov
author_rank: Super Contributor
timestamp: February 06, 2018, 07:27:48 am
content: All Atmel Cortex-M0+ parts have event system and "sleep walking", which is exactly that - peripherals can talk to each other and do simple tasks without waking up the core.I did use that in some projects, but I would not say it is as universal as manufacturers like to make it sound. It is still cool when your problem can be solved this way. And if not, then oh well.

author: llkiwi2006
author_rank: Regular Contributor
timestamp: February 06, 2018, 07:54:38 am
content: It's a cool system but so far the only use I've found is its intended purpose of starting the radio from a timer. Usually interrupts do just fine, although I wonder if the PPI system has any power consumption advantages over using interrupts.

author: westfw
author_rank: Super Contributor
timestamp: February 07, 2018, 07:23:39 am
content: Atmel XMegas also have an "Event System" (similar to the SAMD's, I think.) Some of the new ATtiny chips, too.Microchip PICs have "core independent peripherals", NXP PLC18xx has an "Event Router" - it seems to be a popular idea, aimed at doing more work in low-power modes than would otherwise be normal. It seems like a good idea, being able to set up a timed A2D conversion, or tie random-ish peripheral events to a general purpose DMA channel, or whatever. I don't know that I've seen it used very often yet...

author: Phoenix
author_rank: Frequent Contributor
timestamp: February 08, 2018, 01:46:49 am
content: I've used this sort of thing in power electronics control where the adc sampling must be aligned to the pwm. Can start an adc sequence on a specific pwm counter event (TI TMS320 family). This has been around for a long time but might be becoming more present for low power micros to do more without the processor.Sent from my G8441 using Tapatalk

author: jnz
author_rank: Frequent Contributor
timestamp: February 09, 2018, 04:19:43 am
content: Yea, it does seem to be a strong focus on low power.Thanks for the answers everyone.