Changes in this commit:
- Limit duty_u16() to 65535 and duty_ns() to the period duration.
- Return 0 for pwm.freq() if the frequency has not been set yet.
- Return 0 for pwm.duty_us16() and duty_ns() unless both frequency and
duty cycle have been set.
- Initialize the pin to PWM at the very end of the constructor, to avoid
possible glitches on the pin when setting up the PWM.
This adds support for freq/duty_u16/duty_ns keyword arguments in the PWM
constructor, and adds the PWM.init() method. Using init() without
arguments enables a previously deinit-ed PWM again.
Further changes in this commit:
- Do not start PWM output if only duty was set.
- Stop all PWM slices on soft-reset.
- Fix a bug when changing the freq on a channel pair with duty_ns set.
There were several places where 32-bit integer could overflow with
frequencies of 2^28 Hz or above (~268 MHz). This fixes those overflows and
also introduces rounding for more accurate duty_ns computations.
Signed-off-by: Paul Grayson <pdg@alum.mit.edu>
This changes the freq() and duty_u16() functions to use more simpler, more
accurate formulas, in particular increasing the frequency accuracy from a
few percent to a fraction of a percent in many cases.
Signed-off-by: Paul Grayson <pdg@alum.mit.edu>
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>
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>
