Communication Protocol - ACS ACR33U-A1 Smart Duo Reference Manual

7.0. Communication Protocol

ACR33U-A1 SmartDuo shall interface with the host thru the USB connection. A specification, namely
CCID, has been released within the industry defining such a protocol for the USB chip-card interface
devices. CCID covers all the protocols required for operating smart cards.
The configurations and usage of USB endpoints on ACR33U-A1 SmartDuo 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 ACR33U-A1
SmartDuo 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 ACR33U-A1
SmartDuo have to be sent synchronously. (i.e. bMaxCCIDBusySlots is equal to 01h for
ACR33U-A1 SmartDuo)
The supported CCID features by ACR33 are indicated in its Class Descriptor:
Offset
0
1
2
4
5
6
10
14
18
19
23
ACR33U-A1 SmartDuo Reference Manual
Document Title Here
Document Title Here
Version 1.00
Field Size
bLength
bDescriptorType
bcdCCID
bMaxSlotIndex
bVoltageSupport
dwProtocols
dwDefaultClock
dwMaximumClock
bNumClockSuppor
ted
dwDataRate
dwMaxDataRate
Document Title Here
Value
1 36h Size of this descriptor, in bytes
1 21h CCID Functional Descriptor type
CCID Specification Release Number in
2
0100h
Binary-Coded decimal
2 big slots and 4 SAM slots are
1 05h
available on ACR33U-A1
1 ACR33U-A1 can supply 5.0V to its slot
01h
00000 ACR33U-A1 supports T=0 and T=1
4
003h Protocol
00000
4 Default ICC clock frequency is 4 MHz
FA0h
Maximum supported ICC clock
00000
4
FA0h frequency is 4 MHz
Does not support manual setting of
1
00h
clock frequency
00002
4 Default ICC I/O data rate is 10752 bps
A00h
00054 Maximum supported ICC I/O data rate is
4
344100 bps
024h
Description
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