W66910 Datasheet, PDF (33/81 Pages) Winbond – TE Mode ISDN S/T-Controller with Microprocessor Interface

Data Sheet
7.5 PCM Port
W66910 PCI ISDN S/T-Controller
There are two PCM ports in W66910. Data is transmitted/ received when PFCK1/PFCK2 is HIGH. The frame synchronization
clocks (PFCK1-2) are 8 kHz and the bit synchronization clock (PBCK) is 1.536 MHz.
7.6 D Channel HDLC Controller
There are two HDLC protocols that are used for ISDN layer 2 functions : LAPD and LAPB. Their frame formats are shown
below.
LAPB modulo 8 :
flag address control
(1 octet) (1octet) (1octet)
information
(0 or N octets)
FCS
flag
(2 octets) (1 octet)
Control field bits
I frame
S frame
U frame
76543210
N(R)
P
N(S)
0
N(R)
P/F S S 0 1
M M M P/F M M 1 1
LAPB modulo 128 :
flag address control
(1 octet) (1octet) (1 or 2 octets)
information
(0 or N octets)
FCS
flag
(2 octets) (1 octet)
Control field bits
I frame
S frame
U frame
1st octet
2nd octet
7654321076543210
N(S)
0
N(R)
P
XXXXS S 0 1
N(R)
P/F
M M M P/F M M 1 1
LAPD : modulo 128 only
flag
address
(1 octet) (2 octets)
control
(2 octets)
information
(0 or N octets)
FCS
(2 octets)
flag
(1 octet)
Control field bits
I frame
S frame
U frame
1st octet
2nd octet
7654321076543210
N(S)
0
N(R)
P/F
0 0 0 0SS 0 1
N(R)
P/F
M M M P/F M M 1 1
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Publication Release Date: Feb,2001
Revision 1.0