Nrf52840 ds18b20

RE: Nrf52840 ds18b20

awneil — Thu, 01 Aug 2019 15:40:03 GMT

I see you've now started a separate thread on that:

https://devzone.nordicsemi.com/f/nordic-q-a/50529/nrf52840-ds18b20

RE: Nrf52840 ds18b20

Vasa — Thu, 01 Aug 2019 11:29:38 GMT

Hi, is it possible to use one of hardware timer (for instance timer4) to count delays for 1-wire together with BLE? If so, is it possible to setup HW timer to generate 1us period?

RE: Nrf52840 ds18b20

awneil — Wed, 31 Jul 2019 09:22:37 GMT

[quote userid="80955" url="~/f/nordic-q-a/50426/nrf52840-ds18b20/201437"] i guess the question is done[/quote]

The please verify the answer(s):

RE: Nrf52840 ds18b20

Vasa — Wed, 31 Jul 2019 08:20:02 GMT

Thanks to all, i guess the question is done,

RE: Nrf52840 ds18b20

awneil — Tue, 30 Jul 2019 17:29:55 GMT

In addition to BinderT's suggestions, Maxim make bridge chips to take the 1-wire timing considerations away from the "host" microcontroller:

https://www.maximintegrated.com/en/products/interface/one-wire/bridge-your-app-to-1-wire.html

They also have an app note on how to fake it with a UART:

https://www.maximintegrated.com/en/app-notes/index.mvp/id/214

You could probably do something similar with SPI ...

RE: Nrf52840 ds18b20

BinderT — Tue, 30 Jul 2019 17:03:38 GMT

Hi,

Just a shot in the dark but try setting in the sdk_config.h NRF_SDH_DISPATCH_MODEL to 2 if you have not tried that.

// <i> NRF_SDH_DISPATCH_MODEL_INTERRUPT: SoftDevice events are passed to the application from the interrupt context.
// <i> NRF_SDH_DISPATCH_MODEL_APPSH: SoftDevice events are scheduled using @ref app_scheduler.
// <i> NRF_SDH_DISPATCH_MODEL_POLLING: SoftDevice events are to be fetched manually.
// <0=> NRF_SDH_DISPATCH_MODEL_INTERRUPT 
// <1=> NRF_SDH_DISPATCH_MODEL_APPSH 
// <2=> NRF_SDH_DISPATCH_MODEL_POLLING 

#ifndef NRF_SDH_DISPATCH_MODEL
#define NRF_SDH_DISPATCH_MODEL 2
#endif

The problem is that this BLE needs specific timings and thus most of the highest priority level interrupts are taken by the softdevice, so this will mess with the bit-bang approach of the one-wire protocol. You will save yourself a lot of headache by adding in another micro (or some protocol converter); ATtiny series comes to mind; and use that to pass the data to the NRF via uart, spi or twi.

Regards,