[ell-i-developers] Re: PWM working for TIM2
- From: Ivan Raul <supra.material@xxxxxxxxx>
- To: ell-i-developers@xxxxxxxxxxxxx
- Date: Wed, 29 Jan 2014 23:10:19 +0200
I think the second option looks quite reasonable. I will give it a try
tomorrow. It is the first time I will start writing something a little more
extensive for the system!! :-)
I hope it optimizes as expected.
With Warm Regards, Ivan Raul
On Wed, Jan 29, 2014 at 10:04 PM, Pekka Nikander <pekka.nikander@xxxxxx>wrote:
> >>> To really make the PWM work, still the GPIO alternate functions need
> to be initialized, do I work on that in parallel with the Serial testing?
> >>
> >> Please remind me what this was about?
> >>
> > Is the setting of the alternate functions:
> >
> >
> https://github.com/Ell-i/Arduino/blob/ell-i/hardware/ell-i/stm32/variants/ellduino_stm32f051/stm32f051_init.c#L321
> >
> > Serial sets them in begin routine, but there is not initialization part
> for analogWrite. The timer is activated, but it can't access the pins.
>
> I see. I have completely forgotten that we need to not only activate the
> GPIO peripherals in the RCC register, but also to initialise them for
> analogWrite, SPI, and perhaps other functions. I thought about that back
> in November but alas my memory is too short. (Or there are too many things
> I'm trying to remember. :-)
>
> Anyway, we have here a small architectural problem. Architecturally, each
> GPIO pin is a separate entity, and has a separate mode, output type, output
> speed, pull up/down, and alternate function setting. However, if we just
> simply declare them separately for each pin, we consume quite a lot of
> memory as we would have to define about 6 * 32 bits for each pin. On the
> other hand, if we define each GPIO register initialisation value, as we've
> done in the old runtime, then the definitions for each pin get dispersed
> over several lines in the source code, which is bad from the modularity and
> maintenance point of view.
>
> That is, I'd like to use a macro like
>
> DEFINE_GPIO_PIN_INIT(B, 2, INPUT, ..., AF2);
>
> One line for each pin.
>
> The simple approach would then to generate a simple init record like
> const SystemInitRecordArrayData32NoAddress ... {
> ...
> D32(GPIO_TypeDef, AF[0], GPIO_AFRx_AFRx3_AF2)
>
> However, that would consume excessive memory, as I wrote.
>
> Perhaps we could generate static const values out of the macro, and then
> combine them? Something like
>
> ...
> static const __GPIOB_PIN2_AF = GPIO_AFRx_AFRx3_AF2;
> ...
> const SystemInitRecordArrayData32NoAddress ... {
> ...
> D32(GPIO_TypeDef, AF[0],
> __GPIOB_PIN0_AF |
> __GPIOB_PIN1_AF |
> ...
>
> What do you think? Would that work? Could you perhaps try it, Ivan? Or
> should I?
>
> --Pekka
>
>
>
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