ACR122S – Communication Protocol
Version 2.01
www.acs.com.hk
Page 13 of 57
Offset
Field
Size
Value
Description
6
bSeq
1
Same as Bulk-OUT Sequence number for
corresponding command.
7
bStatus
1
8
bError
1
9
bClockStatus
1
Example:
To deactivate the slot 0 (default), sequence number = 2.
HOST -> 02 63 00 00 00 00 00 02 00 00 00 [Checksum] 03
RDR -> 02 00 00 03
RDR -> 02 81 00 00 00 00 00 02 00 00 00 [Checksum] 03
5.3. Exchanging data through the SAM interface
Command Frame Format
STX (02h)
Bulk-OUT Header
(HOST_to_RDR_XfrBlock)
Parameters Checksum ETX (03h)
1 Byte
10 Bytes
M Byte
1 Byte
1 Byte
HOST_to_RDR_XfrBlock Format
Offset
Field
Size
Value
Description
0
bMessageType
1
6Fh
1
dDwLength
<LSB .. MSB>
4
M
Message-specific data length.
5
bSlot
1
00-FFh Identifies the slot number for this
command. Default=00h
6
bSeq
1
00-FFh Sequence number for command.
7
bBWI
1
00-FFh Used to extend the Block Waiting
Timeout.
8
wLevelParameter
2
0000h
Response Frame Format
STX (02h)
Bulk-IN Header
(RDR_to_HOST_DataBlock)
abData
Checksum ETX (03h)
1 Byte
10 Bytes
N Bytes (ATR)
1 Byte
1 Byte
RDR_to_HOST_DataBlock Format
Offset
Field
Size
Value
Description
0
bMessageType
1
80h
Indicates that a data block is
being sent from the ACR122S.
