TWI and S140 BLE controller conflict on nrf52840 dk using Zephyr

RE: TWI and S140 BLE controller conflict on nrf52840 dk using Zephyr

Sigurd — Wed, 07 Oct 2020 12:55:32 GMT

Great! Happy to help ☺

RE: TWI and S140 BLE controller conflict on nrf52840 dk using Zephyr

JustinL — Wed, 07 Oct 2020 11:56:31 GMT

Brilliant!! Those config settings fixed it immediately. Thank you so much, that had me stuck for several days.

This was using the zephyr version in nrf sdk 1.3.1.

RE: TWI and S140 BLE controller conflict on nrf52840 dk using Zephyr

Sigurd — Wed, 07 Oct 2020 09:58:00 GMT

Hi,

[quote user=""]Are you able to clarify if the Zephyr nrf TWI or TWIM drivers are expected to be compatible with enabling Softdevice Bluetooth controller on Zephyr?[/quote]

Yes, they are expected to be compatible.

What tag/branch/commit are you using ?

How have you configured the stack/heap ?

Do you see any changes if you set the stack/heap like this ?

# Heap and stacks
CONFIG_HEAP_MEM_POOL_SIZE=16384
CONFIG_MAIN_STACK_SIZE=8192
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
CONFIG_HW_STACK_PROTECTION=y

[quote userid="93997" url="~/f/nordic-q-a/66714/twi-and-s140-ble-controller-conflict-on-nrf52840-dk-using-zephyr"]Bluetooth controller in low latency mode[/quote]

Do you see any difference in behavior if you are not using low latency mode?

RE: TWI and S140 BLE controller conflict on nrf52840 dk using Zephyr

JustinL — Tue, 06 Oct 2020 11:02:30 GMT

I have now removed USB CDC initialization and now only log via RTT debug. So I now only have a BT stack and the TWI.
I have also set the TWI priority to be the same as the main thread.

With these changes Bluetooth advertising starts and TWI access works alongside bluetooth.
A BT client can connect and subscribe to a characteristic.

However, when bt_gatt_notify() or bt_gatt_notify_cb() are called (whilst the client is subscribed), a few msec later there is a fatal error.

I have even tried putting the main thread into a while(1) loop after calling bt_gatt_notify(), but still a few msec later crash even though my code is literally doing nothing.

Here is the debug log showing the timing when bt_gatt_notify() is called and the exception.

[00:00:22.843,475]<inf> main: About to call bt_gatt_notify_cb()
[00:00:22.862,823]<inf> main: In ble_send_compressed_quaternion_olny
[00:00:25.315,155]<err> os: ***** USAGE FAULT *****
[00:00:25.315,185]<err> os:   Illegal use of the EPSR
[00:00:25.315,185]<err> os: r0/a1:  0x00000000  r1/a2:  0xe000ed00  r2/a3:  0x20007eb4
[00:00:25.315,185]<err> os: r3/a4:  0x00000000 r12/ip:  0x00000000 r14/lr:  0x000322e1
[00:00:25.315,185]<err> os:  xpsr:  0x60000000
[00:00:25.315,216]<err> os: Faulting instruction address (r15/pc): 0x00000000
[00:00:25.315,216]<err> os: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
[00:00:25.315,216]<err> os: Current thread: 0x2000716c (unknown)
[00:00:27.911,712]<err> fatal_error: Resetting system

Unfortunately with logging on the debugger now has nothing in the stack trace when it breaks on the fault so I can't see what function it is in except that with the while(1) test, it can't be a fault in my code after the bt_gatt_notify is called.

Thanks