![](http://datasheet.mmic.net.cn/310000/STIR4200S_datasheet_16288576/STIR4200S_8.png)
8
3-4200-D1-2.0-0403
STIr4200
USB/IrDA Bridge Controller
O F F I C I A L P R O D U C T D O C U M E N T A T I O N
4.3.3.
Read Multiple Registers
The read multiple registers vendor specific command allows the user to read multi-
ple sequential registers from the Digital IR Transceiver. Each register is one byte
wide, so the command indicates the first register to read, the number of registers to
read, and the responding data phase supplies the data from those registers. This
command is also used for the case of reading only one register.
4.3.4.
Read ROM
The read ROM vendor specific command allows the user to read the contents of the
USB controller endpoint zero ROM. This is primarily a debug feature that allows ver-
ification of the endpoint zero ROM contents. Only 64 bytes of ROM data can be
requested at a time. The responding data phase supplies the data from the endpoint
zero ROM.
4.3.5.
Vendor Clear Stall
The vendor clear stall command is included as a potential work around for limita-
tions in early versions of the Microsoft
USB driver stack. Although not a concern
with the latest operating systems, the earlier versions could have the possibility that
the USB driver stack would not properly clear endpoint stalls. The standard device
clear stall request is also supported.
Offset
Field
Size
Value (hex)
Description
0
1
2
4
6
bmRequestType 1
BRequest
Wvalue
Windex
Wlength
0xc0
0x01
Not used (0x0000)
0x0001
–
0x000f
0x0001
–
0x000f
Table 6. Read Multiple Registers
Device to host, vendor type, device recipient
Read multiple registers
1
2
2
2
First register to read
Number of registers to read
Offset
Field
Size
Value (hex)
Description
0
1
2
4
6
BmRequestType 1
Brequest
Wvalue
Windex
Wlength
0xc0
0x02
Not used (0x0000)
0x0000
–
0x00ff
0x01
–
0x0040
Device to host, vendor type, device recipient
Read ROM
1
2
2
2
Base ROM address
Number of ROM locations to read (64 bytes
max per request)
Table 7. Read ROM
Offset
Field
Size
Value (hex)
Description
0
BmRequestType 1
0x42
Device to host, vendor type, endpoint
recipient
Clear endpoint stall
1
2
4
6
Brequest
Wvalue
Windex
Wlength
1
2
2
2
0x01
Not used (0x0000)
0x0000
–
0x0002 Endpoint on which to clear stall
Not used (0x0000)
Table 8. Vendor Clear Stall