task threads blocking the device connection.

[manoj97]

I'm using the NRF52840 SDK 15.0.0

I have 2 task threads and 5 ble services.

Now what happens is when I'm trying to connect the device with 2 tasks and ble services I'm unable to connect/pair the nrf52 device.

When I comment on one task the device getting paired.

  TASK_MANAGER_CONFIG_STACK_SIZE 4096 

can anyone help me what was the mistake I'm done?

 

[Wavecake]

Can you tell how your firmware fails? A heap/memory problem would crash the firmware. Other kinds of problems may prevent the connection, but you will still be able to confirm the firmware runs without issue by pausing and continuing the debugger. 

[manoj97]

Present heap size is 1024

stack size is 2048

if I want to increase those size what is the value? how it is calculated?

How did my firmware fail?

When I power ON my device and trying to connect my device with nrf connect application.

When I click on connect in nrf connect application it will be in connecting state Foronly not able to connect the device you can see in below photo. 

On application in logs I found this error: Error34(0x22):GATT CONN LMP TIMEOUT

for this I tried to comment on one task then the device is connected immediately.

This is the situation I want those tasks also.

[haakonsh]

At what points does your tasks yield?

[manoj97]

sorry i didn't get your point

[haakonsh]

At what point in your threads do you call task_yield or  task_events_wait?

From Experimental: Task manager docs:

task_create() creates and activates the task. If task is executed it will not be preempted by other task unless task explicitly triggers task switching. Task switch may be triggered by calling task_yield() or task_events_wait(). If task_yield() is called then task manager will switch to next active task. If there is no active task then switch will not occur. If task_events_wait() is called then context switch will occur if there are no events waiting for the task. task_events_wait() returns mask of events. Events are triggered by calling task_events_set() from any context.

[Wavecake]

it doesn't look like they are using the task manager. They are using the FreeRTOS API. 

I think you brought up a good point though. For two tasks at the same level, one will need to yield. In FreeRTOS you have the option to yield or add a delay. They delay effectively provides the yield. They have a delay in the device thread. They are missing a yield or a delay in the oled_thread. 

Try adding taskYield or vTaskDelay() to oled_thread.

I'm not convinced this will solve the issue though. The connection process happens through interrupts, which supersede tasks in priority. They had a problem with the connection process.

[Wavecake]

Use your debugger. Figure out where the program halts when the connection process fails. You should be able to tell if it is a memory issue or not. If the program hits the assert or goes to reset, you'll know it's a memory issue. If the debugger shows that the program continues to execute without issue, you'll know it's not a memory issue. 

Definitely hook up the debugger and post your results.