Octagon 6000 Series, User Manual

Page: 61 / 233

5-12
Serial ports 6000 Series user’s manual
Examples
Full C code examples are included in the \EXAMPLES directory on the
PC Microcontroller utility disk. The following examples are for concept
only.
Example 1:
The following is a description of how Roll Call is implemented:
Host sends: (Dear node #1, are you there?)
>01AA3.
;>
;message start character
; 01 ;intended listener is ID 01
; A ;command code A (roll call)
; A3 ;checksum = uchar (‘0’+‘1’+’A’+0x01) = 0xA3
; . ;message end character
Remote replies: (Dear 00: 01 is here. I have no special request.)
>00Z01007B.
;>
;message start character
; 00 ;intended listener is ID 00 (host)
; Z ;command code Z (reply to roll call)
; 01 ;01 = my ID
; 00 ;00 = status = no special request
; 7B;checksum = uchar (‘0’+‘0’+’Z’ +‘0’+’1’ +‘0’+’0’) = 0x7B
; .;message end character
Host sends: (Dear node #2, are you there?)
>02AA5.
;>
;message start character
; 02 ;intended listener is ID 02
; A ;command code A (roll call)
; A5 ;checksum = uchar (‘0’+‘2’+’A’+0x02) = 0xA5
; . ;message end character
Remote replies: (Dear 00: 02 is here. I have no special request.)
>00Z02007C.
;>
;message start character
; 00 ;intended listener is ID 00 (host)
; Z ;command code Z (reply to roll call)
; 02 ;02 = my ID
; 00 ;00 = status = no special request
; 7C;checksum = uchar (‘0’+‘0’+’Z’ +‘0’+’2’ +‘0’+’0’) = 0x7C
; .;message end character
The host continues with the roll call until all nodes have been queried.
Not all of the 32 possible nodes need to be queried, only the known
nodes. When the last known node has been queried, then the host
queries for an unknown node.