Benutzer:Siro/i2cprotokoll

I2C Protokoll

Version 0.1

DEFINITIONS

layer0	Hardwareebene (i2c)
layer1	Packetebene
endpoint	externe Hardware (nicht näher definiert)

Vorderungen

Alle Devices sollen die max. Busgeschwindigkeit verwenden

Alle Daten werden in Paketen übertragen

Alle Daten werden vom Master "gepollt"

Alle Devices können bis zu 254 Endpoints haben (Endpoint 0 reserved)

Packet

Header	Data
1 Byte	1-8 Byte

Header:

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3 - 0
reserved	reserved	Command/!Data	Parity	Packetsize

Note: Parity can be EVEN, ODD, XOR, NONE, Parity does include packetsize-Bits and all DATA
Note: Command/!DATA marks this packet as COMMAND packet or as DATA packet

COMMAND PACKET
COMMAND PACKET: size >= 1
1. byte: COMMAND
2. - 8. byte:DATA (optional)
handled by layer1

DATA PACKET
handled by userprogram

COMMANDS

0x00
NOP
0x01
GET DEVICE INFO
returns information about the device
max supported protocol version
endpoint count
...
0x02
GET ENDPOINT INFO
2.byte: endpoint
returns information about the endpoint
must be less then max. device endpoints
0x03
SET ENDPOINT
2.byte: endpoint
must be less then max. device endpoints
0x04
GET CURRENT ENDPOINT
return active endpoint (default: 0)
0x05
SEND DATA
sends data to current endpoint (default: 0)
0x05
GET DATA
get data to current endpoint (default: 0)