ACS ACR122 Series User guide

Advanced Card Systems Ltd. Website: www.acs.com.hk
Email: [e-mail]
ACR122 NFC Contactless Smart Card Reader
Application Programming Interface

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CONTENTS
Introduction 4
Features 4
USB interface 4
Contact and Contactless interface handling 5
Pseudo APDUs 6
Basic program flow 10
Card access 13
Appendix 23

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Introduction
The ACR122U is a PC-linked Contactless Cards reader and writer for accessing MIFARE,
ISO14443-4 Type A&B, FeliCa and NFC Tags.
Features
•USB PnP, 12Mbps
•PCSC Interface (API level only)
•CCID Standard
•Built-in Antenna for contactless tags access.
•Bi-Color LED (Rectangular Light Guide).
•Buzzer (optional)
•SAM Socket (optional)
•Compact size: 98 X 65 X 12.8mm
•Reading distance is 40~50mm (depended on the tag type)
•RoHS Compliant
•The ACR122U supports the following Tag Types:
oMIFARE Classic. E.g. MIFARE 1K, 4K and Ultralight
oISO14443-4 Type A and B.
oSony FeliCa. 212 kbps and 424 kbps
oNFC Forum Type 1. E.g. Topaz, Jewel.
USB Interface
The ACR122U is connected to a computer through USB as specified in the USB Specification 1.1.
The ACR122U is working in Full speed mode, i.e. 12 Mbps.
Pin Signal Function
1 V
BUS
+5V power supply for the reader (Max 200mA, Normal
100mA)
2 D- Differential signal transmits data between ACR122U and PC.
3 D+ Differential signal transmits data between ACR122U and PC.
4 GND Reference voltage level for power supply

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Contact and Contactless Interfaces Handling
The contactless interface is operating on the top of contact interface. Some Pseudo APDUs are
defined for contactless interface. If the reader finds that the APDUs are for contactless interface, the
APDUs will be routed to the contactless interface, otherwise, the APDUs will be routed to contact
interface. The Contact and Contactless Interfaces are able to be operating at the same time.
1. The Pseudo APDU “Direct Transmit” is used for sending commands to the contactless interface
Command Class INS P1 P2 Lc Data In
Direct
Transmit
0xFF 0x00 0x00 0x00 Number
of Bytes
to send
PN532_Contactless
Command
2. The Pseudo APDU “Get Response” is used for retrieving the responses from the contactless
interface.
Command Class INS P1 P2 Le
Get Response 0xFF 0xC0 0x00 0x00 Number of Bytes
to retrieve
If the reader finds that the APDU is in the form of “FF 00 00 00 Lc XX XX ..” or “FF C0 00 00
Le”, the APDU will be routed to the contactless interface.
Also, one Pseudo APDU “Bi-Color LED and Buzzer Control” is defined for controlling the LED
and Buzzer.
Command Class INS P1 P2 Lc Data In
(4 Bytes)
Bi-Color and
Buzzer
LED Control
0xFF 0x00 0x40 LED
State
Control
0x04 Blinking Duration
Control
Similarly, if the reader finds that the APDU is in the form of “FF 00 40 XX 04 XX XX XX XX”,
the APDU will be used for setting the LED and Buzzer State.
The control interface must be activated in order to send commands to the contactless or LED
interface

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Pseudo APDUs
PSCS interface is used for exchanging APDUs and Responses between the PC and Tag. The
ACR122U will handle the required protocol internally. ACR122U comes with two primitive
commands for this purpose.
Direct Transmit
To send an APDU (PN532 and Contactless Commands), and the length of the Response Data will
be returned.
Table 1.0A: Direct Transmit Command Format (Length of the PN532_Contactless Command + 5
Bytes)
Command Class INS P1 P2 Lc Data In
Direct
Transmit
0xFF 0x00 0x00 0x00 Number
of Bytes
to send
PN532_Contactless
Command
Lc: Number of Bytes to Send (1 Byte)
Maximum 255 bytes
Data In: PN532_Contactless Command
The data to be sent to the PN532 and Contactless Tag.
Table 1.0B: Direct Transmit Response Format (2 Bytes)
Response Data Out
Result SW1 SW2
Data Out: SW1 SW2
Status Code returned by the reader.
Table 1.0C: Status Code
Results SW1 SW2 Meaning
Success 61 LEN The operation is completed
successfully. The response data has a
length of LEN bytes.
The APDU “Get Response” should
be used to retrieve the response data.
Error 63 00 The operation is failed.
Time Out
Error
63 01 The PN532 does not response.

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Checksum
Error
63 27 The checksum of the Contactless
Response is wrong.
Parameter
Error
63 7F The PN532_Contactless Command is
wrong.
Get Response
To retrieve the response data after the “Direct Command” is issued.
Table 2.0A: Get Response Command Format (5 Bytes)
Command Class INS P1 P2 Le
Get Response 0xFF 0xC0 0x00 0x00 Number of Bytes
to retrieve
Le: Number of Bytes to Retrieve (1 Byte)
Maximum 255 bytes
Table 2.0B: Get Response Format (Le bytes, Length of the Response Data)
Response Data Out
Result Response Data
Data Out: Response Data, or Error Code “63 00” will be given if no response data is
available.
Remark:
In general, the Pseudo APDUs “Direct Transmit” and “Get Response” are used in pairs. Once the
APDU “Direct Transmit” is sent, the reader will return the length of the response data. Then, the
APDU “Get Response” is immediately used to retrieve the actual response data.
Bi-Color LED and Buzzer Control
This APDU is used to control the states of the Bi-Color LED and Buzzer.
Table 3.0A: Bi-Color LED and Buzzer Control Command Format (9 Bytes)
Command Class INS P1 P2 Lc Data In
(4 Bytes)
Bi-Color and
Buzzer
LED Control
0xFF 0x00 0x40 LED
State
Control
0x04 Blinking Duration
Control

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P2: LED State Control
Table 3.0B: Bi-Color LED and Buzzer Control Format (1 Byte)
CMD Item Description
Bit 0 Final Red LED State 1 = On; 0 = Off
Bit 1 Final Green LED State 1 = On; 0 = Off
Bit 2 Red LED State Mask 1 = Update the State
0 = No change
Bit 3 Green LED State Mask 1 = Update the State
0 = No change
Bit 4 Initial Red LED Blinking State 1 = On; 0 = Off
Bit 5 Initial Green LED Blinking State 1 = On; 0 = Off
Bit 6 Red LED Blinking Mask 1 = Blink
0 = Not Blink
Bit 7 Green LED Blinking Mask 1 = Blink
0 = Not Blink
Data In: Blinking Duration Control
Table 3.0C: Bi-Color LED Blinking Duration Control Format (4 Bytes)
Byte 0 Byte 1 Byte 2 Byte 3
T1 Duration
Initial Blinking State
(Unit = 100ms)
T2 Duration
Toggle Blinking State
(Unit = 100ms)
Number of
repetition
Link to Buzzer
Byte 3: Link to Buzzer. Control the buzzer state during the LED Blinking.
0x00: The buzzer will not turn on
0x01: The buzzer will turn on during the T1 Duration
0x02: The buzzer will turn on during the T2 Duration
0x03: The buzzer will turn on during the T1 and T2 Duration.
Data Out: SW1 SW2. Status Code returned by the reader.
Table 3.0D: Status Code
Results SW1 SW2 Meaning
Success 90 Current LED State The operation is completed
successfully.
Error 63 00 The operation is failed.
Table 3.0E: Current LED State (1 Byte)
Status Item Description
Bit 0 Current Red LED 1 = On; 0 = Off
Bit 1 Current Green LED 1 = On; 0 = Off
Bits 2 – 7 Reserved

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Remark:
A. The LED State operation will be performed after the LED Blinking operation is completed.
B. The LED will not be changed if the corresponding LED Mask is not enabled.
C. The LED will not be blinking if the corresponding LED Blinking Mask is not enabled. Also,
the number of repetition must be greater than zero.
D. T1 and T2 duration parameters are used for controlling the duty cycle of LED blinking and
Buzzer Turn-On duration. For example, if T1=1 and T2=1, the duty cycle = 50%. #Duty Cycle =
T1 / (T1 + T2).
E. To control the buzzer only, just set the P2 “LED State Control” to zero.
F. The make the buzzer operating, the “number of repetition” must greater than zero.
G. To control the LED only, just set the parameter “Link to Buzzer” to zero.
Get the Firmware Version of the reader
To retrieve the firmware version of the reader.
Table 4.0A: Get Firmware Version Command Format (5 Bytes)
Command Class INS P1 P2 Le
Get Response 0xFF 0x00 0x48 0x00 0x00
Table 4.0B: Get Firmware Version Response Format (10 bytes)
Response Data Out
Result Firmware Version
E.g. Response = 41 43 52 31 32 32 55 31 30 31 (Hex) = ACR122U101 (ASCII)

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Basic Program Flow for Contactless Applications
Step 0. Start the application. The first thing is to connect the “ACR122U PCSC Interface”. The
ATR of the SAM (if a SAM is inserted) or a Pseudo-ATR “3B 00” (if no SAM is inserted) will
be returned. In other word, the SAM is always existed from the view of the application.
Step 1. The second thing to do is to change the operating parameters of the PN531. Set the
Retry Time to one.
Step 2. Poll a Contactless Tag by using “Direct Transmit” and “Get Response” APDUs (Tag
Polling).
Step 3. If no tag is found, go back to Step 2 until a Contactless Tag is found. #For ISO14443-4
tags polling, it may have to turn off the Antenna Field before starting another polling
process.
Step 4. Access the Contactless Tag by sending Pseudo APDUs. (Direct Transmit and Get
Response)
Step 5. If there is no any operation with the Contactless Tag, then go back to Step 2 to poll the
other Contactless Tag.
..
Step N. Disconnect the “ACR122U PCSC Interface”. Shut down the application.
Remarks:
1) Some Type A Tags may support both ISO14443-3 Type A and ISO14443-4 Type A
operating modes. For example, JCOP30 supports MIFARE 1K emulation (ISO14443-3) and
ISO14443-4. If the reader sends a RATS command to the tag, the ISO14443-4 mode will be
activated, or the tag remains in MIFARE 1K emulation mode (ISO14443-3). It is up to the
application to decide which operating mode to be activated. By default, the reader will
perform automatic ISO14443-4 activation if the tag supports ISO14443-4.
•To disable automatic ISO14443-4 activation: FF 00 00 00 03 D4 12 24
•To Enable automatic ISO14443-4 activation: FF 00 00 00 03 D4 12 34
2) The default Retry Time of the PN532 command “InListPassiveTarget” is infinity. That
means, after the polling command is sent out, the reader will wait until a valid tag is found.
If the application wants to get the immediate result of the polling command, please set the
Retry Time to one
•Set the Retry Time to one: FF 00 00 00 06 D4 32 05 00 00 00

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3) The antenna can be switched off in order to save the power.
•Turn off the antenna power: FF 00 00 00 04 D4 32 01 00
•Turn on the antenna power: FF 00 00 00 04 D4 32 01 01
4) No Automatic Contactless Tag Insertion or Removal Event will be generated. The
Contactless Polling is done by the application.
5) The Contactless Tag is accessed through the use of Pseudo-APDUs “Direct Transmit” and
“Get Response”.
The reader will check the content of the APDU to determine which interface will be used
APDU
Standard APDU for Contact Card?
Or
Pseudo APDU for Contactless Card?
Or
LED and Buzzer Control?
ISO7816 T=0
Contact Interface
ISO14443
Or
ISO18092
Contactless
Interface
LED and Buzzer
Control
SAM Socket
(Optional) Built-in Antenna
Bi-Color LED
And
Buzzer (Optional)
APDU is received by the reader
Standard
APDU for
Contact Card
Pseudo APDU
for Contactless
Card
Pseudo APDU
for LED and
Buzzer Control