w66910 Winbond Electronics Corp America, w66910 Datasheet - Page 68

• Manufacturer Part Number: w66910
• Description: Te Mode Isdn S/t-controller With Microprocessor Interface
• Manufacturer: Winbond Electronics Corp America

0: The data rate in B1 channel is 64 kbps.
1: The data rate in B1 channel is 56 kbps. The most significant bit in each octet is fixed at "1".
Note: In 56 kbps mode, only transparent mode can be used.
FTS1-0 FIFO Threshold Select
These two bits determine the B1 channel receive and transmit FIFO's threshold setting. An interrupt is generated when the
number of received data or the number of vacancies in XFIFO reaches the threshold value.
8.2.5 B1_ch Extended Interrupt Register B1_EXIR
Value after reset: 00H
RMR Receive Message Ready
At least a threshold lenth of data has been stored in the B1_RFIFO.
RME Receive Message End
Used in transparent mode only. The last block of a frame has been received. The frame length can be found in B1_RBCH +
B1_RBCL registers. The number of data available in the B1_RFIFO equals frame lenth modulus threshold. The result of CRC
check is indicated by B1_STAR:CRCE bit.
When the number of last block of a frame equals the threshold, only RME interrupt is generated.
RDOV Receive Data Overflow
Data overflow occurs in the receive FIFO. The incoming data will overwrite the data in the receive FIFO.
XFR Transmit FIFO Ready
This interrupt indicates that up to a threshold length of data can be written into the B1_XFIFO.
XDUN Transmit Data Underrun
This interrupt occurs when the B1_XFIFO has run out of data. In this case, the W66910 will automatically reset the transmitter
and send the inter frame time fill pattern on B channel. The software must wait until transmit FIFO ready condition (via XFR
interrupt), re-write data, and issue XMS command to re-transmit the data.
7
RMR
6
FTS1
0
0
1
1
RME
5
FTS0
0
1
0
1
RDOV
4
Threshold (byte)
Not allowed
Reserved
3
64
96
2
-68 -
XFR
1
Read_clear
XDUN
0
W66910 PCI ISDN S/T-Controller
Address 24H
Publication Release Date:
Data Sheet
Revision 1.0
Feb,2001