Editing Very Simple Control Protocol (section)

==VSCP event datagram structure==
Events that are broadcast contain a number of fields together forming one VSCP datagram. Exactly how these fields are mapped onto the physical layer is specified for a number of physical layer protocols such as CAN, Ethernet, TCP, etc. For others it is not yet
defined, but it is in general not difficult to map these fields onto a physical layer protocol. There are 2 ''levels'' of the VSCP protocol called ''LEVEL I'' & ''LEVEL II''. They are both basically the same protocol but differ in size of the different fields.

Level I is intended to run on nodes with more constrained resources and fields are defined a bit more conservatively. Level I is in fact a subset of level II, and with an appropriate gateway events can transverse between a Level I & II network.

{| class="wikitable" border="1"
|+ VSCP datagram level I
|-
! Priority
! Hardcoded ID
! CLASS
! TYPE
! SenderNickID
! DataSize
! Payload
! CRC
|-
| 3 bits
| 1 bit
| 9 bits
| 8 bits
| 8 bits
| 4 bits
| 0 to 8 bytes
| 16 bits
|}

Level II is intended to be run on nodes that have little resource constraints and can easily cope with larger message sizes.

{| class="wikitable" border="1"
|+ VSCP datagram level II
|-
! Priority
! Hardcoded ID
! CLASS
! TYPE
! SenderGUID
! DataSize
! Payload
! CRC
|-
| 3 bits
| 1 bit
| 16 bits
| 16 bits
| 128 bits
| 16 bits
| 0 to 487 bytes
| 16 bits
|}