This patch brings the _thread module to stmhal/pyboard. There is a very
simple round-robin thread scheduler, which is disabled if there is only
one thread (for efficiency when threading is not used).
The scheduler currently switches threads at a rate of 250Hz using the
systick timer and the pend-SV interrupt.
The GIL is disabled so one must be careful to use lock objects to prevent
concurrent access of objects.
The threading is disabled by default, one can enabled it with the config
option MICROPY_PY_THREAD to test it out.
It turns out that TIM1 and TIM8 have their own Capture/Compare
interrupt vector. For all of the other timers, the capture/compare
interrupt vector is the same as the update vector.
So we need to add handlers for these vectors and enable them
when using capture/compare callbacks.
During testing of this, I also found that passing a channel callback
into the channel constructor would not enable interrupts properly.
I tested using:
```
>>> pyb.Timer(1, freq=4).channel(1, pyb.Timer.OC_TOGGLE, callback=lambda t: print('.', end=''))
```
I tested the above with channels 1, 4, and 8
TIM3 is no longer used by USB CDC for triggering outgoing data, so we
can now make it available to the user.
PWM fading on LED(4) is now gone, but will be reinstated in a new way.
Previous to this patch the USB CDC driver used TIM3 to trigger the
sending of outgoing data over USB serial. This patch changes the
behaviour so that the USB SOF interrupt is used to trigger the processing
of the sending. This reduces latency and increases bandwidth of outgoing
data.
Thanks to Martin Fischer, aka @hoihu, for the idea and initial prototype.
See PR #1713.
Adds a lot of code, makes IRQs a bit less efficient, but is very useful
for debugging. Usage: pyb.irq_stats() returns a memory view that can be
read and written, eg:
list(pyb.irq_stats())
pyb.irq_stats()[0]
pyb.irq_stats()[0] = 0
The patch provides general IRQ_ENTER() and IRQ_EXIT() macros that can be
modified to provide further IRQ statistics if desired.
This is refactoring to enable support for the two USB PHYs available on
some STM32F4 processors to be used at the same time. The F405/7 & F429
have two USB PHYs, others such as the F411 only have one PHY.
This has been tested separately on a pyb10 (USB_FS PHY) and F429DISC
(USB_HS PHY) to be able to invoke a REPL/USB. I have modified a PYBV10
to support two PHYs.
The long term objective is to support a 2nd USB PHY to be brought up as a
USB HOST, and possibly a single USB PHY to be OTG.
This is a hack to free up TIM3 so that it can be used by the user.
Instead we use the PVD irq to call the USB VCP polling function, and
trigger it from SysTick (so SysTick itself does not do any processing).
The feature is enabled for pyboard lite only, since it lacks timers.
The STMCube examples define both USE_USB_HS and USE_USB_HS_IN_FS when they
use the HS in FS mode.
The STM32F401 doesn't have a USB_HS at all, so the USB_OTG_HS instance
doesn't even exist.
uwTick can only change in the SysTick IRQ so this IRQ function does not
need to take special care with this variable. It's important to make
this IRQ function as efficient as possible.
Using SysTick to do the counting and dispatch of the flash storage idle
handler is more efficient than requiring a dedicated hardware timer.
No new counter is needed, just the existing uwTick variable. The
processing is not actually done in the SysTick IRQ, it is deferred to
the flash IRQ (which runs at lower priority).
Turning on each DMA block increases the current consumption
by about 8 mA. This code adds an idle timer for each DMA
block and turns off the clocks when no streams are in use
for 128 msec. Having a small timeout allows for improved
performance when back-to-back transfers are being performed.
The 128 msec is basically a guess.
py/mphal.h contains declarations for generic mp_hal_XXX functions, such
as stdio and delay/ticks, which ports should provide definitions for. A
port will also provide mphalport.h with further HAL declarations.
