Support for Raspberry RP2040

[ahorn42]

Support for Raspberry RP2040

[orgua]

That's mostly Atmel-related lowlevel-stuff to access pins that was needed to allow the fast overdrive-mode of Onewire. Maybe it's time to remove all that error-prone platform-glue and use arduino-commands by default.
I will order a RP2040 and look into either porting the lib or advance to pure-arduino as a major v3-step

[ahorn42]

Just found the calibrate_by_bus_timing script and it seems to work now with IPL = 25 :)

Unfortunately I still don't understand what the other values mean that were configured in platform.h

#define PIN_TO_BASEREG(pin)             (portInputRegister(digitalPinToPort(pin)))
#define PIN_TO_BITMASK(pin)             (digitalPinToBitMask(pin))
#define DIRECT_READ(base, mask)         (((*(base)) & (mask)) ? 1 : 0)
#define DIRECT_MODE_INPUT(base, mask)   ((*((base)+1)) &= ~(mask))
#define DIRECT_MODE_OUTPUT(base, mask)  ((*((base)+1)) |= (mask))
#define DIRECT_WRITE_LOW(base, mask)    ((*((base)+2)) &= ~(mask))
#define DIRECT_WRITE_HIGH(base, mask)   ((*((base)+2)) |= (mask))
using io_reg_t = uint8_t; // define special datatype for register-access

Above is the sample for AVR, I kind of have an idea what it should do, but I think I need some further hints how to adapt this to the RP2040 ;)