Microscan MS-4X User Manual page 356

Communications Protocol
Setup 2
Address 0x01 (translates to) Poll Req @ '0x1C', Unit Select @ '0x1D'
RES 0x04
REQ 0x05
STX 0x02
ETX 0x03
ACK 0x06
NAK 0x15
LRC enabled
Transfer 1
HOST_TX
IMAGER_TX
HOST_TX
IMAGER_TX
HOST_TX
Transfer 2
HOST_TX
IMAGER_TX
IMAGER_TX
HOST_TX
Starting with a 'RES' ensures a clean transaction, without "leftovers" from the previous
transaction.
Error Condition 1
HOST_TX
IMAGER_TX
HOST_TX
timeout reached...
IMAGER_TX
timeout reached...
IMAGER_TX
timeout reached...
IMAGER_TX
timeout reached...
IMAGER_TX
A-22
'RES' '0x1D' 'REQ' (Select Unit 1 to receive data)
'0x1D' 'ACK' (Unit responds with its address)
'STX' <T> 'ETX' 'LRC'
'0x1D' 'ACK' (Unit responds with its address)
'RES' (Terminate Transfer 2)
'RES' '0x1C' 'REQ' (Poll Unit 1 for data)
'0x1C' 'STX' <T/00000> 'ETX' 'LRC'
'ACK'
'RES' (Terminate Transfer 1)
'RES' '0x1C' 'REQ' (Poll Unit 1 for data)
'0x1C' 'STX' <T/00000> 'ETX' 'LRC'
'Nothing' (Host should 'ACK' here)
'REQ' (Unit requests an 'ACK' again)
'REQ' (Unit requests an 'ACK' again)
'REQ' (Unit requests an 'ACK' again)
'RES' (Terminate Transfer 1, data is flushed)
MS-4X Imager User's Manual