nrf52840 ds18b20

[Vasa]

hi, team.

I've got a question. I use nrf52840 dev board. There is a connection between nrf52840 and ds18b20. I tried to use dedicated HW timer to count delay according to 1-wire spec. And i faced 2 problems:

1. i'd like to setup HW timer to generate 1us, but instead i got only 13us (1us expected). I check this using oscilloscope and toogle GPIO pin in timer interrupt.

2. Anyway i decided to use HW timer to count delay for ds18b20, but the problem is that i can't leave timer interrupt, so the program won't go further, stuck in timer interrupt.

So, is it possible to achive 1us interrupt on nrf52840? Is it possible to use dedicated HW timer to count delay for ds18b20?

[awneil]

Vasa said:

i'd like to setup HW timer to generate 1us, but instead i got only 13us (1us expected).

Show your code

Vasa said:

Is it possible to use dedicated HW timer to count delay for ds18b20

I don't know for sure, but I suspect not.

As noted in your other thread, you'd probably be better off either using an external chip to do the timing, or faking it on the UART or SPI

https://devzone.nordicsemi.com/f/nordic-q-a/50426/nrf52840-ds18b20

One thing to note is that the 1-Wire timing is only critical within a bit timeslot  - the timing between bits is completely non-critical.

The SoftDevice has a Timeslot API - which might be useful to schedule the 1-Wire bit timeslot into places where the radio won't interrupt...?

https://infocenter.nordicsemi.com/topic/sds_s140/SDS/s1xx/concurrent_multiprotocol_tsl_api/radio_tsl_api.html