This repository contains golang tools to

• capture packets from a serial device
• verify integrity of the received packets
• decode the P1/P2 packets
• display the data using a HTTP server
• interface 3rdparty tools

The tools are designed to work with my custom PCB P1P2_HBS_USBCdc_Modem

Based on the awesome documentation on P1P2Serial and observations on DAIKIN EJHA04AAV3.

The gateway tool located in cmd/gateway allows to interface with the "P1P2 bus" serial device. It exposes

• a REST HTTP server
• a prometheus client
• a HTTP POST client for Home Assistant
• a web UI in human readable form

You need to create a YAML config to properly use the gateway. Some fields are optional.

prometheus:
  enable: true
  port: 2112
  ListenAddress: ""
html:
  enable: true
  asset_path: /var/
  port: 80
  listen_address: ""
serial:
  enable: true
  device: /dev/ttyAMA0
  baud_rate: 115200
  parity: ""
  stop_bits: 1
homeassistant:
  enable: true
  hostname: localhost
  port: 8123
  bearer: "ABCDEFGH"

If you want to interface your P1P2 bus exposed on serial device /dev/ttyAMA0 with Home Assistant running on the same machin, then provide the following config.

1. Get the bearer token from Home Assisant to authenticate on the REST API.

2. Create a new config /etc/p1p2_gateway/p1p2.yaml

serial:
  enable: true
  device: /dev/ttyAMA0
  baud_rate: 115200
homeassistant:
  enable: true
  hostname: localhost
  bearer: "ABCDEFGH"

(Replace "ABCDEFGH" with your private token!)

3. Run the gateway application from cmd/gatway The gateway application will automatically create sensors and post sensor data if new data has been received on the serial. No further configuration is necessary on Home Assistant.

The following packets from the P1P2 bus are decoded:

• Packet 10h Req/Resp
• Packet 11h Req/Resp
• Packet 12h Req/Resp
• Packet 13h Resp
• Packet 14h Resp
• Packet 16h Resp
• Packet b8h Resp

Those happen between the heat pump and the controller unit and can be captured using a passive P1P2 sniffer.

Applications are located in cmd folder.

The decoding library is located in pkg folder.

• P1P2Serial
• P1P2_HBS_USBCdc_Modem
• Home Assistant