ACR89U-A2 – Reference Manual
Version 1.01
www.acs.com.hk
Page 7 of 57
3.0. ACR89 USB Communication Protocol
ACR89 interfaces with host (in PC-linked mode) with USB connection. CCID specifications have been
released within the industry defining such protocol for the USB chip-card interface devices. CCID
covers all the protocols required for operating smart cards and PIN. However, it does not define the
protocol for operating other peripheral features that ACR89 also has. Communication protocol for
ACR89 reader shall follow the CCID specifications and extend it to support the rest of the reader’s
features.
3.1. Device Configuration
The configurations and usage of USB end-points on ACR89 shall follow CCID Section 3. An overview
is summarized below:
1.
Control Commands
are sent on control pipe (default pipe). These include class-specific
requests and USB standard requests. Commands that are sent on the default pipe report
information back to the host on the default pipe.
2.
CCID Events
are sent on the interrupt pipe.
3.
CCID Commands
are sent on BULK-OUT endpoint. Each command sent to ACR89 has an
associated ending response. Some commands can also have intermediate responses.
4.
CCID Responses
are sent on BULK-IN endpoint. All commands sent to ACR89 have to be
sent synchronously. (i.e.
bMaxCCIDBusySlots
is equal to 1 for ACR89).
The supported CCID features by ACR89 are indicated in its Class Descriptor:
Offset
Field
Size
Value
Description
0
bLength
1
36h
Size of this descriptor, in bytes
1
bDescriptorType
1
21h
CCID Functional Descriptor type
2
bcdCCID
2
0100h
CCID Specification Release
Number in Binary-Coded decimal
4
bMaxSlotIndex
1
04h
Five slots are available on ACR89.
5
bVoltageSupport
1
07h
ACR89 can supply 1.8V, 3.0V and
5.0V to its slots
6
dwProtocols
4
00000003h
ACR89 supports T=0 and T=1
Protocol
10
dwDefaultClock
4
000012C0h
Default ICC clock frequency is 4.8
MHz
14
dwMaximumClock
4
000012C0h
Maximum supported ICC clock
frequency is 4.8 MHz
18
bNumClockSupported
1
00h
Does not support manual setting of
clock frequency
19
dwDataRate
4
003267h
Default ICC I/O data rate is 12,903
bps
23
dwMaxDataRate
4
00032673h
Maximum supported ICC I/O data
rate is 206,451 bps
27
bNumDataRatesSupported
1
00h
Does not support manual setting of
data rates
28
dwMaxIFSD
4
00000FEh
Maximum IFSD supported by
ACR89 for protocol T=1 is 254