7.0.Communication Protocol
ACR100F interfaces with the host via USB connection. It is a compounded device consisting of two
interfaces: Chip Card Interface Device and Mass Storage.
The ACR100F 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 ACR100F 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 ACR100F 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 bDescriptorTyp
e 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 bVoltageSuppor
t 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 bNumClockSuppo
rted 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 bNumDataRatesS
upported 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
32 dwSynchProtoco
ls 4 00000000h The Smart card reader does not support
synchronous card
36 dwMechanical 4 00000000h The Smart card reader does not support
special mechanical characteristics
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ACR100F (CCID) Reference Manual
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