ACS ACR3801, Reference Manual

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ACR3801 – Reference Manual
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7.0. Communication Protocol
ACR3801 shall interface with the host through 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 ACR3801 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 ACR3801 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 ACR3801 have to be
sent synchronously (e.g., bMaxCCIDBusySlots is equal to 01h for ACR3801).
ACR3801 supported CCID features 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 ACR3801
5 bVoltageSupport 1 07h
ACR3801 can supply 1.8 V, 3 V, and
5 V to its slot
6 dwProtocols 4 00000003h ACR3801 supports T=0 and T=1
protocol
10 dwDefaultClock 4 00000FA0h Default ICC clock frequency is 4 MHz
14 dwMaximumClock 4 00000FA0h Maximum supported ICC clock
frequency is 4 MHz
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 bNumDataRatesSupported 1 00h
Does not support manual setting of data
rates
28 dwMaxIFSD 4 00000FEh Maximum IFSD supported by ACR3801
for protocol T=1 is 254
32 dwSynchProtocols 4 00000000h ACR3801 does not support synchronous
card
36 dwMechanical 4 00000000h ACR3801 does not support special
mechanical characteristics