PT7A6632 Datasheet, PDF (29/61 Pages) Pericom Semiconductor Corporation – PT7A6632 32-Channel HDLC Controller

Data Sheet
PT7A6632 32-Channel HDLC Controller
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• FILL/MASK Byte (Rate Definition)
The FILL/MASK byte is used as a masking pattern on the
HDLC-formatted (including FLAG, header, data, CRC, and
ABORT code) or non-HDLC-formatted data in order to adapt
subrates that are multiples of 8kb/s to the 64kb/s rate. The 8-
bit sequence is applied to data on a bit by bit basis to insert 1
(FILL/MASK bit = 0) for time fill, or insert data bit (FILL/
MASK = 1). See an example in Figure 6 in Section “Transmit
Bit-Level Processor” and Table 9.
For bit-oriented signaling mode, the FILL/MASK should be
set as 1111 1111. If not, the PT7A6632 will not override any
other FILL/MASK pattern.
Table 9. Examples of FILL/MASK Options
Bit
Option Data
Number Rate 7 6 5 4 3 2 1 0
(MSB)
(LSB)
Remar ks
0*
0 kb/s 0
0 000
0
0
0
No data will be sent. Eight 1s for time fill will
be sent if TSEREN=1.
1
8 kb/s
0
0
0 000
0 10 0
0
0
0
0
1 Arbitrary-user defined; a 1 in any one bit
0 position, but only one 1.
0 0 10 0 0 1 0
2
16 kb/s
0
0
000 1
0 0 10
10
10
0 User defined pattern; a 1 in any two bit
0 positions, but only two 1s.
1 1000 0 0 0
3
24 kb/s
0
0
0 000
10 10
1
1
1
0
1
0
A total of three 1s anywhere as defined by user.
0 000 1 1 1 1
4
32 kb/s 1 1 1 1 0 0 0 0 A total of four 1s anywhere as defined by user.
1 0 10 1 0 1 0
5 40 kb/s 0 0 0 1 1 1 1 1 A total of five 1s anywhere as defined by user.
6 48 kb/s 0 0 1 1 1 1 1 1 A total of six 1s anywhere as defined by user.
0 1 1 1 1 1 1 1 Standard rate in digital data service, restricted
7
56 kb/s
version of 64 kb/s.
1 1 1 1 1 1 1 0 A total of seven 1s anywhere as defined by user.
8 64 kb/s 1 1 1 1 1 1 1 1
* A special purpose mode in which the transmitter operates as if it is at 64 kb/s, including when it is fetching data from
the external memory, even though no data is transmitted.
PT019(05/02)
29
Ver:2