Adding a timer to a BLE application

RE: Adding a timer to a BLE application

Susheel Nuguru — Tue, 22 May 2018 07:14:54 GMT

This thread is complete with a proper answer.

Your description is very little and not enough to conclude that your problem is related to this thread. I would strongly recommend you to create a new thread and try to get an answer. Please remember to be as descriptive as possible to get response from fellow enthusiastic devzone users

RE: Adding a timer to a BLE application

Nordic_nRF52840 — Tue, 08 May 2018 18:16:59 GMT

Hi Hieu,

Were you able to resolved your problem? it appears that I have the same problem

when I tried to add TIMER1 to the project sample "ble_app_uart" .

Any advise is appreciated. Looking forward to your reply.

Regards,

JIMMY

RE: Adding a timer to a BLE application

Hieu — Thu, 21 Jan 2016 05:02:31 GMT

Figured out what happened. Thanks for the tips, RK.

RE: Adding a timer to a BLE application

Hieu — Thu, 21 Jan 2016 05:02:02 GMT

Thanks to the tips from RK, I dived into the product specification and driver structure, and found the root of the problem.

As RK said, TIMER0 cannot be used for anything because it is used by the SoftDevice
Short answer is because TIMER1 is a 16-bit timer.

2.1. While nrf_drv_timer_ms_to_ticks() does check for overflow, it only check if the ticks value is more than 32 bit. The function does not check if the ticks value is too big for the current timer. TIMER1 is only a 8/16 bit timer, so any ticks value greater than 0x0000ffff will have its MS 4 byte clipped off. My ticks value was 0xf42400, which means the actual value written on to the Capture/Compare register is 0x2400, about 1800 times shorter than intended.

2.2. NRF_DRV_TIMER_DEFAULT_CONFIG(1) set TIMER1 to 16MHz, too fast to set an interrupt interval of 1s with a 16-bit Capture/Compare register. A custom nrf_drv_timer_config_t need to be passed for the second param of nrf_drv_timer_init() instead of NULL.

RE: Adding a timer to a BLE application

Hieu — Thu, 21 Jan 2016 03:04:55 GMT

That makes sense. May be it is just me but I have always had some difficulty grasping what the SoftDevice affect. Perhaps because I cannot ever trace back the reference chain back to its code.
The issue is that I cannot find out the frequency. Tracing back the reference link from the timer init function lead to a dead end, with a certain _CONFIG_FREQUENCY. I could never trace any further to find out what that value is. Perhaps I will try to go into debug mode and dig further. Will update here once I did.

RE: Adding a timer to a BLE application

RK — Wed, 20 Jan 2016 11:15:03 GMT

1.1 no it's something else - its the softdevice and documented in the softdevice docs

1.2 n/a

don't know yet

2.1 Why don't you break there and find out what value it's worked out and see if it makes sense given your timer frequency. If that's default it should be 16,000 or 0x3e80.

2.2 NRF_DRV_TIMER_DEFAULT_CONFIG (in the same documentation) which uses the TIMER1_CONFIG_FREQUENCY etc etc defines in the same file you enabled the timer.