Async kb

Terms:

connection: data transfer session, highest in hierarchy

block: data transfer unit, consists of several frames

frame: lowest data transfer unit. basically -- one network message

Message type ==

• 0x80 = data
• 0x90 = command

---

commands:

Request Session

.data[0] = 0xca -- request session

parameters:

.data[1] = priority (always 1)

.data[2] , .data[3] -- message packet max size (16 bit, big endian)

.data[4] == 0x01 (revision)

Session Granted

.data[0] = 0xf2 -- session granted

parameters:

.data[1] = number of frames per block

.data[2] = revision (always 0x01)

.data[3] = priority acknowledge (should reply with the same priority requested)

.data[4] .data[5] = bytes per frame (maximum allowed bytes per frame, 16bit, bigendian)

Starting Transfer

.data[0] = 0xfd

no parameters

Frame Acknowledge

.data[0] = 0xfa (frame acknowledge)

parameters

.data[1]= total number of frames in this block

.data[2]= id of received message

.data[3]= id of current block

Frame Not Acknowledged

.data[0] = 0xfa

.data[1] = 0x00

.data[2] = 0x00

params :

.data[3] = id of current block

Single Frame Request

.data[0] = 0xfb

.data[1] = 0x00

parameters:

.data[2] = id of requested frame in current block

Current block request

.data[0] = 0xfb

.data[1] = 0x00

.data[2] = 0x00