ACS ACR122L User manual

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www.acs.com.hk
Communication Protocol V1.03
ACR122L
Serial NFC Reader
with LCD

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Table of Contents
1.0. Introduction ............................................................................................................... 4
2.0. Features ..................................................................................................................... 5
2.1. Serial Interface.......................................................................................................................5
2.2. LCD........................................................................................................................................5
2.3. LEDs ......................................................................................................................................6
2.4. Buzzer....................................................................................................................................6
2.5. SAM Interface ........................................................................................................................6
2.6. Built-in Antenna .....................................................................................................................6
3.0. Communication between the host and contactless interface, SAM and
peripherals............................................................................................................................. 7
4.0. Serial Interface (CCID-like Frame Format) .............................................................. 8
4.1. Protocol Flow Examples ........................................................................................................9
5.0. SAM Interface .......................................................................................................... 11
5.1. Activating the SAM Interface ...............................................................................................11
5.2. Deactivating the SAM Interface ...........................................................................................12
5.3. Exchanging data through the SAM Interface.......................................................................14
6.0. Pseudo-APDUs for contactless interface and peripherals control .................... 17
6.1. Direct Transmit ....................................................................................................................17
6.2. Change Communication Speed...........................................................................................20
6.3. Get firmware version............................................................................................................24
6.4. LCD Display (ASCII Mode) ..................................................................................................25
6.5. LCD Display (GB Mode) ......................................................................................................28
6.6. LCD Display (Graphic Mode)...............................................................................................29
6.7. Scroll Current LCD Display..................................................................................................30
6.8. Pause LCD Scrolling............................................................................................................31
6.9. Stop LCD Scrolling ..............................................................................................................32
6.10. Clear LCD ............................................................................................................................32
6.11. LCD Backlight Control .........................................................................................................32
6.12. LCD Contrast Control ..........................................................................................................33
6.13. LED Enable/Disable.............................................................................................................34
6.14. LED Control .........................................................................................................................34
6.15. LED and Buzzer Control ......................................................................................................35
6.16. Buzzer Control .....................................................................................................................41
6.17. Basic program flow for ISO 14443-4 Type A and B tags.....................................................41
6.18. Basic program flow for Mifare applications..........................................................................43
6.18.1. Handling the value blocks of Mifare 1K/4K tag ...........................................................45
6.18.2. Accessing Mifare Ultralight tags..................................................................................47
6.18.3. Accessing Mifare Ultralight C tags ..............................................................................49
6.19. Basic program flow for FeliCa applications .........................................................................53
6.20. Basic program flow for NFC Forum Type 1 tag applications...............................................54
Appendix A. ACR122 Error Codes.................................................................................. 56
List of Figures
Figure 1 : Communication Flowchart of ACR122L................................................................................. 7
Figure 2 : Character Set A.................................................................................................................... 26
Figure 3 : Character Set B.................................................................................................................... 27
Figure 4 : Character Set C ................................................................................................................... 27
Figure 5 : LCD Display Position ........................................................................................................... 29

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List of Tables
Table 1 : PIN Configuration .................................................................................................................... 5
Table 2 : DDRAM Address for Font Sets 1 and 2 ................................................................................ 25
Table 3 : DDRAM Address for Font Set 3 ............................................................................................ 26
Table 4 : LCD Character Position Representation ............................................................................... 28
Table 5 : Scrolling Period...................................................................................................................... 31
Table 6 : Scrolling Direction.................................................................................................................. 31
Table 7 : Mifare Ultralight Memory Map ............................................................................................... 49
Table 8 : Mifare Ultralight C Memory Map............................................................................................ 53

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1.0.Introduction
The ACR122L serial protocol defines the interface between the PC and reader, as well as the
communication channel between the PC and the supported contactless tags/cards – ISO 14443-4
Type A and B, Mifare, ISO 18092 (NFC), and FeliCa. The major applications supported are the
following:
•Access Control, Identification: Reading the serial numbers of all cards in the field.
•Data Storage: Performing encrypted read-and-write operations.
•Ticketing: Performing read, write, increment and decrement operations in an encrypted
environment.
•Multi-applications: Performing read, write, increment and decrement operations on various
sectors of the card.

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2.0.Features
•Serial RS-232 Interface: Baud Rate = 115200 bps, 8-N-1
•7 V DC adaptor for power supply
•CCID-like frame format (Binary format)
•Smart Card Reader:
oRead/Write speed of up to 424 kbps
oBuilt-in antenna for contactless tag access, with card reading distance of up to 50 mm
(depending on tag type)
oSupport for ISO 14443 Part 4 Type A and B cards, Mifare, FeliCa and all four types of
NFC (ISO/IEC 18092) tags
oBuilt-in anti-collision feature (only one tag is accessed at any time)
oThree ISO 7816 compliant SAM slots
•Built-in Peripherals:
oTwo-line graphic LCD with interactive operability (i.e. scroll up and down, left and right,
etc.) and multi-language support (i.e. Chinese, English, Japanese and several European
languages)
oFour user-controllable LEDs
oUser-controllable buzzer
•Compliant with the following standards:
oISO 14443
oCE
oFCC
oVCCI
oRoHS
2.1. Serial Interface
The ACR122L is connected to a Host through the RS232C Serial Interface at 115200 bps, 8-N-1
Table 1: PIN Configuration
2.2. LCD
A user-controllable LCD is provided.
•2 line x 16 character, 5 x 8 dot matrix, STN yellow-green LCD type
•Yellow-green backlight
•6 O’clock view angle
Pin Signal Function
1 VCC +7 V power supply for the reader (max. 350 mA; normal 200 mA)
2 TXD The signal from the reader to the host.
3 RXD The signal from the host to the reader.
4 GND Reference voltage level for power supply

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2.3. LEDs
Four user-controllable single color LEDs are provided.
•Control can be selected by firmware or by user.
•From left to right, the colors of the LEDs are green, blue, orange and red.
2.4. Buzzer
A user-controllable monotone buzzer with a default state of OFF is provided.
2.5. SAM Interface
Three SAM sockets, supporting ISO 7816-1/2/3 T=0 cards, are provided.
2.6. Built-in Antenna
A 3-turn symmetric loop antenna, center-tapped, is provided.
•Estimated size is 46 mm x 64 mm.
•Loop inductance is approximately 1.6 μH to 2.5 μH.
•Operating distance for different tags, is approximately up to 50 mm (depends on the tag).
•Only one tag can be accessed at any one time.

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3.0.Communication between the host and contactless
interface, SAM and peripherals
The contactless interface and peripherals are accessed through the use of pseudo-APDUs.
The SAM interface is accessed through the use of standard APDUs.
Figure 1: Communication Flowchart of ACR122L
Serial
Interface
(CCID-like
protocol)
ISO 7816 Parts 1-3
+
T=0 SAM Interfaces
Contactless
Interface
SAM 1
Contactless Tag
(Built-in Antenna)
Host
ACR122L
PCSC Layer
Peripherals
SAM 3SAM 2
RF
Interface

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4.0.Serial Interface (CCID-like Frame Format)
In normal operation, the ACR122L acts as a slave device with regard to the communication between a
computer and the reader. The communication is carried out in the form of successive command-
response exchanges. The computer transmits a command to the reader, and then receives a
response from the reader after the command has been executed. A new command can be transmitted
to the ACR122L only after the response to the previous command has been received. There are two
cases where the reader transmits data without having received a command from the computer,
namely, the Reset Message of the reader and the Card Status Message.
Note: Communication setting: 115200 bps, 8-N-1.
The communication protocol between the host and ACR122L is very similar to the CCID protocol.
ACR122L Command Frame Format
STX (02h) Bulk-OUT Header APDU Command or
Parameters Checksum ETX (03h)
1 Byte 10 Bytes M Bytes (If applicable) 1 Byte 1 Byte
ACR122L Status Frame Format
STX (02h) Status Checksum ETX (03h)
1 Byte 1 Byte 1 Byte 1 Byte
ACR122L Response Frame Format
STX (02h) Bulk-IN Header APDU Response or abData Checksum ETX (03h)
1 Byte 10 Bytes N Bytes
(If applicable) 1 Byte 1 Byte
Checksum = XOR {Bulk-OUT Header, APDU Command or Parameters}
Checksum = XOR {Bulk-IN Header, APDU Response or abData}
For control SAM Socket 1, the STX must be equal to 02h and ETX must be equal to 03h.
For control SAM Socket 2, the STX must be equal to 12h and ETX must be equal to 13h.
For control SAM Socket 3, the STX must be equal to 22h and ETX must be equal to 23h.
For control access Contactless interface, Peripherals (i.e. LEDs, LCD and Buzzer), the STX must be
equal to 02h and ETX must be equal to 03h, which is the same with control SAM Socket1.
In general, we would make use of three types of Bulk-OUT Header:
•HOST_to_RDR_IccPowerOn:To activate the SAM interface. The ATR of the SAM will be
returned if available.
•HOST_to_RDR_IccPowerOff:To deactivate the SAM interface.
•HOST_to_RDR_XfrBlock:To exchange APDUs between the host and ACR122L.
The SAM1 interface must be activated in order to use the contactless interface and peripherals. In
short, all the APDUs are exchanged through the SAM interface.

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Similarly, two types of Bulk-IN Header are used:
•RDR_to_HOST_DataBlock: In response to the HOST_to_RDR_IccPowerOn and
HOST_to_RDR_XfrBlock Frames.
•RDR_to_HOST_SlotStatus:In response to the HOST_to_RDR_IccPowerOff Frame.
RDR = ACR122L; HOST = Host Controller.
HOST_to_RDR = Host Controller -> ACR122L
RDR_to_HOST = ACR122L -> Host Controller
4.1. Protocol Flow Examples
(Use SAM Interface 1 as Example)
A. Activate a SAM.
HOST RDR
1. HOST sends a frame. 02 62 00 00 00 00 00 01 01 00 00 [Checksum] 03
2. RDR sends back a
positive status frame
immediately.
02 00 00 03 (positive status frame) 
.. After some processing delay...
3. RDR sends back the
response of the
command.
02 80 0D 00 00 00 00 01 00 00 00 3B 2A 00 80 65
24 B0 00 02 00 82 90 00 [Checksum] 03 
B. Activate a SAM (Incorrect Checksum, HOST)
HOST RDR
1. HOST sends a
corrupted frame. 02 62 00 00 00 00 00 01 01 00 00 [Incorrect Checksum] 03
2. RDR sends back a
negative status frame
immediately.
02 FF FF 03 (negative status frame) 
3. HOST sends the frame
again. 02 62 00 00 00 00 00 01 01 00 00 [Checksum] 03
4. RDR sends back a
positive status frame
immediately.
02 00 00 03 (positive status frame) 
.. After some processing delay..
5. RDR sends back the
response of the
command.
02 80 0D 00 00 00 00 01 00 00 00 3B 2A 00 80 65
24 B0 00 02 00 82 90 00 [Checksum] 03 

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C. Activate a SAM (Incorrect Checksum, RDR).
HOST RDR
1. HOST sends a frame. 02 62 00 00 00 00 00 01 01 00 00 [Checksum] 03
2. RDR sends back a
positive status frame
immediately.
02 00 00 03 (positive status frame) 
.. After some processing delay...
3. RDR sends back the
response (corrupted) of
the command.
4. HOST sends a NAK
frame to get the
response again.
5. RDR sends back the
response of the
command.

02 80 0D 00 00 00 00 01 00 00 00 3B 2A 00 80 65
24 B0 00 02 00 82 90 00 [Incorrect Checksum] 03
02 00 00 00 00 00 00 00 00 00 00 00 03 (NAK)
02 80 0D 00 00 00 00 01 00 00 00 3B 2A 00 80 65
24 B0 00 02 00 82 90 00 [Checksum] 03


Note: If the frame sent by the HOST is correctly received by the RDR, a positive status frame = {02
00 00 03} will be sent to the HOST immediately to inform the HOST the frame is correctly received.
The HOST has to wait for the response of the command. The RDR will not receive any more frames
while the command is being processed.
In case of errors, a negative status frame will be sent to the HOST to indicate the frame is either
corrupted or incorrectly formatted.
CheckSum Error Frame = {02 FF FF 03}
Length Error Frame = {02 FE FE 03}. The length “dDwLength” is greater than 0105h bytes.
ETX Error Frame = {02 FD FD 03}. The last byte is not equal to ETX “03h”.
TimeOut Error Frame = {02 FC FC 03}. Not Complete Package Received.
The NAK Frame is only used by the HOST to get the last response.
{02 00 00 00 00 00 00 00 00 00 00 00 03} // 11 zeros