Communication protocol – ACS ACR33U-A1 SmartDuo Smart Card Reader User Manual

Page 10

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ACR33U-A1 – Reference Manual

[email protected]

Version 1.02

www.acs.com.hk

Page 10 of 60

7.0. Communication Protocol

ACR33U-A1 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 ACR33U-A1 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 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 have to

be sent synchronously (e.g., bMaxCCIDBusySlots is equal to 01h for ACR33U-A1).

The ACR33U-A1 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

05h

2 big slots and 3 SAM slots are available

on ACR33U-A1

5

bVoltageSupport

1

01h

ACR33U-A1 can supply 5 V to its slot

6

dwProtocols

4

00000003h ACR33U-A1 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

00054024h Maximum supported ICC I/O data rate is

344100 bps

27

bNumDataRatesSupported

1

00h

Does not support manual setting of data

rates

28

dwMaxIFSD

4

00000FEh Maximum IFSD supported by ACR33U-

A1 for protocol T=1 is 254

32

dwSynchProtocols

4

00000000h ACR33U-A1 does not support

synchronous card

36

dwMechanical

4

00000000h ACR33U-A1 does not support special

mechanical characteristics

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