Previously they used historical "pyb" affix causing confusion and
inconsistency (there's no "pyb" module in modern ports; but people
took esp8266 port as an example, and "pyb" naming kept proliferating,
while other people complained that source structure is not clear).
In order to have more fine-grained control over how builtin functions are
constructed, the MP_DECLARE_CONST_FUN_OBJ macros are made more specific,
with suffix of _0, _1, _2, _3, _VAR, _VAR_BETEEN or _KW. These names now
match the MP_DEFINE_CONST_FUN_OBJ macros.
All functionality of the pyb module is available in other modules, like
time, machine and os. The only outstanding function, info(), is
(temporarily) moved to the esp module and the pyb module is removed.
Most pin I/O can be done just knowing the pin number as a simple
integer, and it's more efficient this way (code size, speed) because it
doesn't require a memory lookup to get the pin id from the pin object.
If the full pin object is needed then it can be easily looked up in the
pin table.
PWM implementation uses a timer and interrupts (FRC1), taken from
Espressif's/NodeMCU's implementation and adapted for our use.
8 channels are supported, on pins 0, 2, 4, 5, 12, 13, 14, 15.
Usage:
import machine
pwm0 = machine.PWM(machine.Pin(0))
pwm0.freq(1000)
pwm0.duty(500)
Frequency is shared (ie the same) for all channels. Frequency is
between 1 and 1000. Duty is between 0 and 1023.
Damien George
Paul Sokolovsky
Radomir Dopieralski
Josef Gajdusek