ChibiOS Free Embedded RTOS

Actually, that cleaned up both, so it was that interval that changed definition in the newer code.

Previously I had the interval set to 2, so I set it to 1 now, this fixes the strange relationship with the prescalar.

Now I just need to figure out the other timing differential.

Maybe I am misunderstanding how the interval works now.

Before I'd basically set my frequency to 2x the rate I wanted ...

I thought you could change which clock a timer is referencing?

One thing I notice is that in gpt_lld_start_timer, the interval has been changed.

Previously it was:

gptp->tim->ARR = (uint32_t)(interval - 1)

Now it is:

gptp->tim->ARR = (uint32_t)(interval);

Lots of little changes all over ...

I'm on 17.6.3 now, previously I was on 2.6.6.

The switch to tickless mode was the biggest change I did, so I am thinking something relative to that is what I am dealing with. Since I was using TIM2 already, I set this:

#define STM32_ST_USE_TIMER 5

I verified my clock settings in CubeMX just to ...

Also note, my pre scalar values do not work now.

The code above detects when the pre scalar goes larger than 16-bit, so it keeps bit shifting (*2) the frequency and bit shifting the pre scalar (/2) till the value is in range for the timer. (this was necessary because I need to run the timer at a ...

In the process of updating my code to a newer version of ChibiOs my GPT frequency seems wrong.

Hooking up an output derived from the GPT shows 1.333Hz instead of 2Hz. Multiplying the frequency internal by 1.5 speeds up the clock to 2Hz.

I tried in both tick and tickless mode, works the same.

I ...

Thanks for the information, only reason I asked here was if anyone had done this. Makes sense that the way it is probably written is to have a small footprint as well, so expectations of the processor state make sense.

If I decide to proceed on further, I will shoot a question over to the ST boards.

Is it possible to exit out of my application into DFU mode once I am executing my code?

Right now I have a button on my circuit that you have to hold down when powering up. I'd rather just make an option through my UI while running to go into DFU mode.

Am I am able to do this? Using the STM32F427 ...

I definitely agree that what you have makes sense, because if not, a developer wouldn't know they were getting an inaccurate value because of rounding. In this case, I didn't want to pay the penalty of multiple computation calls so I just let it round it and disabled that particular check.

Found out why it was halting, was this line:

osalDbgAssert(((uint32_t)(psc + 1) * gptp->config->frequency) == gptp->clock,
"invalid frequency");


In my code, I am okay with frequency not being an exact multiple of the clock because it is based on external measurement of signals and I am fine ...