Communication protocol – ACS ACR101 SIMicro (CCID) User Manual
Page 9
7.0. Communication Protocol
ACR101 (CCID) interfaces with the host via USB connection. It is a compounded device consisting of
two interfaces: Chip Card Interface Device and Mass Storage.
The ACR101 (CCID) Smart Card Interface shares the same core as the smart card interface of the
ACR38 CCID. The Smart Card Interface will be identified as “ACR38-112c” once the reader FW is
obtained. (The command for this will be discussed later on). CCID covers all the protocols required for
operating smart cards and PIN.
The configurations and usage of USB endpoints on ACR101 (CCID) Smart Card Interface 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 smart card reader
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 the smart card
reader have to be sent synchronously. (i.e. bMaxCCIDBusySlots is equal to 1)
The supported CCID features by ACR101 (CCID) smart card interface 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
00h
One slot is available
5
bVoltageSupport
1
07h
The Smart card reader can
supply 1.8V, 3.0V and 5.0V
to its slot.
6
dwProtocols
4
00000003h
The Smart card reader
supports T=0 and T=1
Protocol
10
dwDefaultClock
4
00000FA0h
Default ICC clock frequency
is 4MHz
14
dwMaximumClock
4
00000FA0h
Maximum supported ICC
clock frequency is 4MHz
18
bNumClockSupported
1
00h
Does not support manual
setting of clock frequency
19
dwDataRate
4
00002A00h
Default ICC I/O data rate is
10752 bps
23
dwMaxDataRate
4
0001F808h
Maximum supported ICC I/O
data rate is 344 kbps
27
bNumDataRatesSupport
ed
1
00h
Does not support manual
setting of data rates
28
dwMaxIFSD
4
00000Feh
Maximum IFSD supported
by the smart card reader for
protocol T=1 is 254
Document Title Here
Document Title Here
Document Title Here
ACR101 PC/SC Memory Card Access
Version 1.0
Page 9 of 19
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