Communication protocol – ACS ACR100I SIMFlash II User Manual
Page 9
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ACR100I Reference Manual
Version 1.00
Page 9 of 20
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7.0. Communication Protocol
ACR100I shall interface with the host with through USB connection. A specification, namely CCID,
has 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.
The configurations and usage of USB endpoints on ACR100I shall follow CCID Section 3. An
overview is summarized below:
1. Control Commands are sent on a 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 ACR100I 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 ACR100I have to be
sent synchronously. (i.e. bMaxCCIDBusySlots is equal to 1 for ACR100I)
The supported CCID features by ACR100I 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 on ACR100I
5
bVoltageSupport
1
07h
ACR100I can supply 1.8V, 3.0V
and 5.0V to its slot
6
dwProtocols
4
00000
003h
ACR100I supports T=0 and T=1
Protocol
10
dwDefaultClock
4
00000
FA0h
Default ICC clock frequency is
4MHz
14
dwMaximumClock
4
00000
FA0h
Maximum supported ICC clock
frequency is 4MHz
18
bNumClockSupported
1
00h
Does not support manual setting
of clock frequency
19
dwDataRate
4
00002
A00h
Default ICC I/O data rate is
10752 bps
23
dwMaxDataRate
4
0001F
808h
Maximum supported ICC I/O
data rate is 250000 bps
27
bNumDataRatesSuppor
ted
1
00h
Does not support manual setting
of data rates
28
dwMaxIFSD
4
00000
Feh
Maximum IFSD supported by
ACR100I for protocol T=1 is 254