HFC-SUSB Cologne Chip AG, HFC-SUSB Datasheet - Page 17

• Manufacturer Part Number: HFC-SUSB
• Description: Isdn S/t HDLC Basic Rate Controller
• Manufacturer: Cologne Chip AG

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3.1
A full speed 12MBps USB interface is integrated in the HFC-S USB. It is compliant to USB
specification 1.1. The USB interface does not use an internal microcontroller. So code development is
obsolete and power consumption is reduced to a minimum.
3.1.1 Register access by USB interface
The internal registers of the HFC-S USB are accessed by USB vendor specific device requests by the
host. The register address and (for write accesses) the data to be written must be passed in the setup
packet parameters like shown in the table below (see also: Universal Serial Bus Specification Revision
1.1, chapter 9.3).
Table 1: Setup packet parameters for register access
Name
HFC_REG_WR
HFC_REG_RD
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Offset
0
1
2
3
4
5
6
Functional description
USB interface
bmRequestType
(high byte)
(high byte)
(low byte)
(low byte)
bRequest
wLength
wValue
wValue
wIndex
wIndex
Field
Value
0000h
0001h
Size
1
1
1
1
1
1
2
Value
40h for writing data
C0h for reading data
HFC_REG_WR or
HFC_REG_RD
data
ignored
register address
ignored
0000h for write,
0001h for read
Description
bRequest value for register write access.
bRequest value for register read access.
Description
direction=host-to-device, type=vendor,
recipient=device
direction=device-to-host, type=vendor,
recipient=device
specific request for register write
(HFC_REG_WR) or register read access
(HFC_REG_RD).
For write commands this field contains
the byte-sized value to be written to the
register. This value is ignored in read
commands.
All registers of the HFC-S USB have 8
bits so the high byte is ignored.
For read and write commands this field
must contain the register address.
All registers of the HFC-S USB have an
one byte address so the high byte is
ignored.
Only read accesses return data.
Cologne
Chip
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