A C R 3 8 S m a r t C a r d R e a d e r / W r i t e r
Commands
The commands executed by the ACR38 can generally be divided into two categories, namely, Control
Commands and Card Commands.
Control Commands control the internal operation of the ACR38. They do not directly affect the card inserted
in the reader and are therefore independent of the selected card type.
Card Commands are directed toward the card inserted in the ACR38. The structure of these commands and the data
transmitted in the commands and responses depend on the selected card type.
Control Commands
GET_ACR_STAT
This command returns relevant information about the particular ACR38 model and the current operating status, such as, the
firmware revision number, the maximum data length of a command and response, the supported card types, and whether a
card is inserted and powered up.
Command format
Header
Instruction
Data length
01
H
01
H
00
H
00
H
Response data format
Header
Status
Data length
INTERNAL
MAX_C
MAX_R
C_TYPE
C_SEL
C_STAT
LEN
01
H
INTERNAL
10 bytes data for internal use only
MAX_C
The maximum number of command data bytes.
MAX_R
The maximum number of data bytes that can be requested to be transmitted in a response.
C_TYPE
The card types supported by the ACR38. This data field is a bitmap with each bit
representing a particular card type. A bit set to '1' means the corresponding card type is
supported by the reader and can be selected with the
SELECT_CARD_TYPE
command.
The bit assignment is as follows:
Byte 1
2
card type
15
14 13 12
11 10 9 8 7 6 5 4 3 2 1 0
See Appendix A for the correspondence between these bits and the respective card types.
C_SEL
The currently selected card type as specified in a previous
SELECT_CARD_TYPE
command.
A value of 00
H
means that no card type has been selected.
C_STAT
Indicates whether a card is physically inserted in the reader and whether the card is powered
up:
00
H
: no card inserted
ACR38 Reference Manual
Version 2.2 January 2008
Page
11
of 44
