XR21B1424_17 Datasheet, PDF (31/64 Pages) Exar Corporation – Enhanced 4-Ch Full-Speed USB UART

XR21B1424
Table 6: Standard Interrupt Packet Format
Offset
Field
0
bmRequestType
1
bNotification
2
wValue
4
wIndex
6
wLength
8
Data
Size
(Bytes)
Value
1
8’b10100001
1
8’h20
2
16’h0000
2
16’h0000
2
16’h0002
2
Standard
int_status
See Table 7
Description
D7 = Device-to-host direction
D6:5 = Class Type
D4:0 = Interface Recipient
Defined encoding for SERIAL_STATE
D15:8 = Reserved (0)
D7:0 = Interface number, 8’h00 for the
CDC Command Interface
2 bytes of transferred data
D15-7 = Reserved (0)
D6 = bOverRun
D5 = bParity
D4 = bFraming
D3 = bRingSignal (RI)
D2 = bBreak
D1 = bTxCarrier (DSR)
D0 = bRxCarrier (CD)
Table 7: Data Field of Standard Interrupt Packet
Bit
D15:7
D6
Field
bOverRun
D5
bParity
D4
bFraming
D3
bRingSignal
D2
bBreak
D1
bTxCarrier
D0
bRxCarrier
Description
Reserved (future use)
Received data has been discarded due to overrun in
the device.
A parity error has occurred.
A framing error has occurred.
State of ring signal detection of the device.
State of break detection mechanism of the device.
State of transmission carrier. This signal corresponds
to V.24 signal 106 and RS-232 signal DSR.
State of receiver carrier detection mechanism of
device. This signal corresponds to V.24 signal 109
and RS-232 signal DCD.
If the MaxLinear vendor specific packet mapping is enabled then the interrupt packet format is as shown in Table 8.
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