Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 225)

Detailed Flowcharts
Appendix D
DĆ21
Figure D.26
GETCODE Subroutine
GETCODE
GETRAW
Get Byte from UART
DLE
?
GETRAW
Get Byte from UART
DLE
?
No
Yes
BCC
Add Data Bytes
to BCC
Return Byte
and Data Flag
Save ACK or
NAK in RESP
WAKEUP
Resume XMIT
if Sleeping
at WTRESP
ACK or NAK
?
Yes
No
No
Yes
No
Yes
ETX
?
Return Byte
and Control Flag
GET RAW
GET BCC
BCC
Include in Check
GETRAW
CRC
Return EXT
and Control Flag
11679
Output
•
BYTE: What was received?
•
Control/Data: Set if BYTE is
a control character which was
preceded by a DLE.
NOTE: BCC should now equal zero.