This project aims to access the 2-wire interface on Daikin heap pump systems called P1/P2. It's inspired by Arnold-n/P1P2Serial, but builds on a RPI hat using the RPI PICO as P1/P2 modem.

The modem uses ADC Chan1/Chan2 in round robin mode for RX and PIO0 for TX.

While the TX part needs no CPU cycles (except pushing to the PIO TX FIFO), the RX path occupies the whole Cortex-M0+ CPU core.

The code makes use of the pico-sdk. It's linked as submodule so you need to check it out first:

cd pico
git submodule update --init --checkout --recursive
cmake .
make

It generates an U2F file in pico/src/p1p2.uf2 that can be copied to the USB mass storage devices emulated by the Pico.

• 16x Oversampling on TX

• 32x Differential oversampling on RX providing 9bit
• 7-step FIR filter
• Resampler after FIR to 16x Oversampling
• P1/P2 decoder detecting parity, frame and polarity errors