Using pins D9 & D10 on the MDBT42Q

so are you actually calling the SETNFC() method? you might also try setting some global variable inside the uicr flashing method sent to NRF.restart to verify it is really called.
like var done=0 and adding done=1 after poke32(0x4001e504, 0);while(!peek32(0x4001e400));

Tried that @fanoush. its not calling the code inside the restart function it appears

@Gordon, I am really stuck here. We've got PCBs made and it was in hindsight a bad idea to use the NFC pins for straight GPIO work....

there is no prompt to put into bootloader mode...nothing else happens.

That's a bit strange... The IDE should work.

However maybe you could try using the Nordic App to do the upload (http://www.espruino.com/MDBT42Q#firmware-updates) that's what we usually suggest

I got the latest FW in using the ULR link as I mentioned but the write register commands aren't working for me....

I just tested with device I just have here - nrf52840 dongle and indeed have some issues with this if I connect over bluetooth. However when I connect over USB serial it worked. Can you try over serial console without using bluetooth console at all?
this was over serial

>var d=0
=0
> NRF.disconnect();NRF.restart(function(){d=1;})
>d
=1

when tried bluetooth

>var d=0
=0
Disconnected from Web Bluetooth, Dongle c56e
>NRF.disconnect();NRF.restart(function(){d=1;})
Found NRF52840Dongle, 2v08.156
>
Connected to Dongle c56e
>d
=0

I also tried without NRF.Disconnect - you need to disconenct after calling it, it prints

>NRF.restart(function(){d=1;})
BLE Connected, queueing BLE restart for later
=undefined

and should restart later but d is still 0 after reconnecting.
Strange, this worked previously. Not 100%, sometimes I saw this too, but mostly it worked fine. If this happened previously, after E.reboot() it worked.

Thanks @fanoush, Am I missing something as my MDBT42Q has no USB connector?

yes, it has only serial console on pins mentioned here
https://github.com/espruino/Espruino/blob/master/boards/MDBT42Q.py#L23

Oh ok. I use TTL Serial devices all the time.. missed that. I'll try it but for the production pcbs this will be a pain to connect serial and override the register.

I'll try it but for the production pcbs this will be a pain to connect serial and override the register.

It shouldn't be required, but hopefully this will help to narrow down if it is the issue.

Actually I just had a thought. Try:

NRF.disconnect();setTimeout(function() { NRF.restart(function(){ LED.set();
poke32(0x4001e504,1);while(!peek32(0x4001e400)); // enable flash writing
poke32(0x1000120c,0xfffffffe);while(!peek32(0x4001e400)); // NFC pins as GPIO
poke32(0x4001e504, 0);while(!peek32(0x4001e400)); // disable flash writing
})}, 1000)

It's possible the disconnect isn't instant and so NRF.restart doesn't get called.

Thankyou @Gordon, that works... I've put in the extra semi-colons...

NRF.disconnect();setTimeout(function() { NRF.restart(function(){ LED.set();
poke32(0x4001e504,1);while(!peek32(0x4001e400)); // enable flash writing
poke32(0x1000120c,0xfffffffe);while(!peek32(0x4001e400)); // NFC pins as GPIO
poke32(0x4001e504, 0);while(!peek32(0x4001e400)); // disable flash writing
});}, 1000);

Great! I'll update the previous post

It's possible the disconnect isn't instant and so NRF.restart doesn't get called.

Strange that when you are still connected it tell you this BLE Connected, queueing BLE restart for later and so it is actually not called at all after disconnect? Because this didn't work too.

I'm struggling to find the link to the Nordic app to try..Must be missing the obvious

it is actually not called at all after disconnect? Because this didn't work too.

It is called, but it won't execute the JS you gave it :)

I'm struggling to find the link to the Nordic app to try

For firmware updates?

http://www.espruino.com/Puck.js#firmware-updates

You really did mean an app (not going down that route)... I've just sent someone instructions to use the URL approach but firmware zip file might change so it won't be right. the local file select function just doesn't work which is a shame. Tried it numerous times..

@Gordon, for clarity, why do we need to restart the "softdevice" to be able to use the poke32 functions?

You really did mean an app (not going down that route)

You mean you never install any apps on your phone? Honestly the NRF Connect app is harmless, ad-free, and very useful when developing with Bluetooth LE.

why do we need to restart the "softdevice" to be able to use the poke32

poke32 works totally fine with the softdevice running on most addresses, but there's a certain level of memory protection added while the softdevice (bluetooth stack) is running - it doesn't want you to be able to modify internal registers like UICR.

So what we do is disable the Bluetooth stack, write them, and restart it. You also have to fully reset the device after setting the registers in order for the pins to work.

But you only ever have to do this once for each device.

Many thanks for that. Will look at the app then. Its probably more the downloading firmware files from a remote location...

I'm not entirely sure I understand the concern here as I imagine this is something you'd do at the factory (or if you're ordering a bunch of MDBT42 from us we can arrange that they are pre-flashed with newer firmware). The Nordic App works from a file saved locally on your Android device.

However you're welcome to host the firmware files yourself on your own server if that's an issue.

Will try it....

Will look at the app then. Its probably more the downloading files from a remote location...

It is an app for Android or iPhone in builtin Google or Apple app store so no downloading of random files. NRF Connect app is made directly by Nordic Semiconductor for testing BLE and flashing Nordic chips. https://www.nordicsemi.com/Software-and-tools/Development-Tools/nRF-Connect-for-mobile

As for poke32 - those 0x4001exxx addresses used are accessing low level NVMC hardware to directly write/erase flash memory. Doing this is protected because it would interrupt bluetooth timing - when writing to flash the CPU is completely halted until write is done which can take relatively long. So the softdevice manages flash access while it is running and writes to flash are carefully timed to not to break bluetooth traffic.

If you run that code while bluetooth is on it will immediately reboot.

If you haven't sorted this, any chance you could try this code:

NRF.disconnect();setTimeout(function() { NRF.restart(function(){
poke32(0x4001e504,1);while(!peek32(0x4001e400)); // enable flash writing
poke32(0x1000120c,0xfffffffe);while(!peek32(0x4001e400)); // NFC pins as GPIO
poke32(0x4001e504, 0);while(!peek32(0x4001e400)); // disable flash writing
}) }, 2000);

It might be the timeout helps since it's possible the board hadn't disconnected right after NRF.disconnect was called.

@Gordon, apologies for not replying initially. It all worked before and tried the above code as well and it changes the registers as intended.
This then means that the NFC pins that had stopped working as GPIO now work again which is what I was trying to prove all along.....