W6694 Datasheet, PDF (16/33 Pages) Winbond – USB Bus ISDN S/T-Controller

Preliminary W6694
B1_DATA
B1 Channel Data
These are B1 channel data, the length is indicated by B_LEN.
B2_DATA
B2 Channel Data
These are B2 channel data, the length is indicated by B_LEN.
7.1.7 Isochronous-IN Transaction (Endpoint 5)
After power on or reset, all B and D channels receive FIFO (RFIFO) are disabled. A disabled RFIFO
can not receive data from ISDN, and will always return zero-length data for Isochronous-IN
transaction. RFIFO can only be enabled by command CMDR:REN. Once enabled, an Isochronous-
IN transaction can read data from RFIFO of that channel. The data packet also carries XFIFO status
for that channel, and the most recent Isochronous-OUT packet error status (if error ever occurred).
Note that since B1 and B2 channel output length is the same in Isochronous-OUT packet, the XFIFO
status of B1/B2 channels are the same.
The packet format of Isochronous-IN is as below:
Bit 7
ISOE
D_XFR
6
D_XCOL
B1_XFR B1_XDOV
B2_XFR B2_XDOV
5
4
3
D_XDOV
B1_XDUN
B2_XDUN
D_XDUN D_RDOV
D_DATA
...
B1_RDOV B1_LEN3
B1_DATA
...
B2_RDOV B2_LEN3
B2_DATA
...
2
D_LEN2
B1_LEN2
B2_LEN2
1
D_LEN1
B1_LEN1
B2_LEN1
0
D_LEN0
B1_LEN0
B2_LEN0
ISOE Isochronous-OUT Error
This bit is set to indicate that the most recent received Isochronous-OUT packet has CRC
error. This bit will remain set, until a CMDR1:CISOE clears it.
XCOL Transmit Collision (D channel only)
This bit indicates a D channel collision on the S-bus has been detected. The data in D
channel XFIFO will be automatically re-transmitted, until the whole HDLC frame are
successfully transmitted. This bit will remain set, until software issue CMDR1:DXEN to clear
this bit.
XFR Transmit FIFO Ready
It is set when XFIFO has at least half of the XFIFO size available for incoming USB data.
XDUN Transmit Data Under-run
The corresponding XFIFO has run out of data. For D and B channel, the XFIFO is reset and
disabled for that channel. This bit is cleared when XFIFO is enabled by XEN bit.
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