This commit prevents the device from "hanging" when using lightsleep while
the WiFi chip is active.
Whenever the WiFi chip wants to interrupt the microcontroller to notify it
for a new package, it sets the CYW43_PIN_WL_HOST_WAKE pin to high,
triggering an IRQ. However, as polling the chip cannot happen in an
interrupt handler, it subsequently notifies the pendsv-service to do a poll
as soon as the interrupt handler ended. In order to prevent a new
interrupt from happening immediately afterwards, even before the poll has
run, the IRQ handler disables interrupts from the pin.
The first problem occurs, when a WiFi package arrives while the main loop
is in cyw43-code. In order to prevent concurrent access of the hardware,
the network code blocks pendsv from running again while entering lwIP code.
The same holds for direct cyw43 code (like changing the cyw43-gpios, i.e.
the LED on the Pico W). While the pendsv is disabled, interrupts can still
occur to schedule a poll (and disable further interrupts), but it will not
run. This can happen while the microcontroller is anywhere in rp2040 code.
In order to preserve power while waiting for cyw43 responses,
cyw43_configport.h defines CYW43_DO_IOCTL_WAIT and
CYW43_SDPCM_SEND_COMMON_WAIT to __WFI(). While this might work in most
cases, there are 2 edge cases where it fails:
- When an interrupt has already been received by the cyw43 stack, for
example due to an incoming ethernet packet.
- When the interrupt from the cyw43 response comes before the
microcontroller entered the __WFI() instruction.
When that happens, wfi will just block forever as no further interrupts are
received. The only way to safely use wfi to wake up from an interrupt is
inside a critical section, as this delays interrupts until the wfi is
entered, possibly resuming immediately until interrupts are reenabled and
the interrupt handler is run. Additionally this critical section needs to
check whether the interrupt has already been disabled and pendsv was
triggered, as in such a case, wfi can never be woken up, and needs to be
skipped, because there is already a package from the network chip waiting.
Note that this turns cyw43_yield into a nop (and thereby the cyw43-loops
into busy waits) from the second time onwards, as after the first call, a
pendsv request will definitely be pending. More logic could be added, to
explicitly enable the interrupt in this case.
Regarding lightsleep, this code has a similar problem. When an interrupt
occurs during lightsleep, the IRQ and pendsv handler and thereby poll are
run immediately, with the clocks still disabled, causing the SPI transfers
to fail. If we don't want to add complex logic inside the IRQ handler we
need to protect the whole lightsleep procedure form interrupts with a
critical section, exiting out early if an interrupt is pending for whatever
reason. Only then we can start to shut down clocks and only enable
interrupts when the system is ready again. Other interrupt handlers might
also be happy, that they are only run when the system is fully operational.
Tested on a Pico W, calling machine.lightsleep() within an endless loop and
pinging from the outside.
This gets basic machine.lightsleep([n]) behaviour working on the rp2 port.
It supports:
- Calling lightsleep without a specified period, in which case it uses xosc
dormant mode. There's currently no way to wake it up from this state,
unless you write to raw registers to enable a GPIO wake up source.
- Calling lightsleep with a period n in milliseconds. This period must be
less than about 72 minutes and uses timer alarm3 to wake it up.
The RTC continues to run during lightsleep, but other peripherals have
their clock turned off during the sleep.
It doesn't yet support longer periods than 72 minutes, or waking up from
GPIO IRQ.
Measured current consumption from the USB port on a PICO board is about
1.5mA when doing machine.lightsleep(5000), and about 0.9mA when doing
machine.lightsleep().
Addresses issue #8770.
Signed-off-by: Damien George <damien@micropython.org>
It's no longer needed because this macro is now processed after
preprocessing the source code via cpp (in the qstr extraction stage), which
means unused MP_REGISTER_MODULE's are filtered out by the preprocessor.
Signed-off-by: Damien George <damien@micropython.org>
This commit adds I2S protocol support for the rp2 port:
- I2S API is consistent with STM32 and ESP32 ports
- I2S configurations supported:
- master transmit and master receive
- 16-bit and 32-bit sample sizes
- mono and stereo formats
- sampling frequency
- 3 modes of operation:
- blocking
- non-blocking with callback
- uasyncio
- internal ring buffer size can be tuned
- DMA IRQs are managed on an I2S object basis, allowing other
RP2 entities to use DMA IRQs when I2S is not being used
- MicroPython documentation
- tested on Raspberry Pi Pico development board
- build metric changes for this commit: text(+4552), data(0), bss(+8)
Signed-off-by: Mike Teachman <mike.teachman@gmail.com>
This commit refactors machine.PWM and creates extmod/machine_pwm.c. The
esp8266, esp32 and rp2 ports all use this and provide implementations of
the required PWM functionality. This helps to reduce code duplication and
keep the same Python API across ports.
This commit does not make any functional changes.
Signed-off-by: Damien George <damien@micropython.org>
Initial support for machine.RTC on rp2 port. It only supports datetime()
method and nothing else. The method gets/returns a tuple of 8 items, just
like esp32 port, for example, but the usec parameter is ignored as the RP2
RTC only works up to seconds precision.
The Pico RTC isn't very useful as the time is lost during reset and there
seems to be no way to easily power up just the RTC clock with a low current
voltage, but still there seems to be use-cases for that, see issues #6831,
and a Thonny issue #1592. It was also requested for inclusion on v1.15
roadmap on #6832.
Signed-off-by: Krzysztof Adamski <k@japko.eu>
When UART is used for REPL and the MCU frequency is changed, the UART
has to be re-initialised. Besides that the UART may have to be recreated
after a frequency change, but with USB REPL this is not a problem.
Thanks to @HermannSW for spotting and providing the change.
Using the standard machine.freq().
The safe ranges tested were 10 and 12-270MHz, at which USB REPL still
worked. Requested settings can be checked with the script:
pico-sdk/src/rp2_common/hardware_clocks/scripts/vcocalc.py. At frequencies
like 300MHz the script still signaled OK, but USB did not work any more.
This commit adds a new port "rp2" which targets the new Raspberry Pi RP2040
microcontroller.
The build system uses pure cmake (with a small Makefile wrapper for
convenience). The USB driver is TinyUSB, and there is a machine module
with most of the standard classes implemented. Some examples are provided
in the examples/rp2/ directory.
Work done in collaboration with Graham Sanderson.
Signed-off-by: Damien George <damien@micropython.org>
Felix Dörre