pef20320 Infineon Technologies Corporation, pef20320 Datasheet - Page 76

• Manufacturer Part Number: pef20320
• Description: Multichannel Network Interface Controller For Hdlc With 32 Channels
• Manufacturer: Infineon Technologies Corporation

User’s Manual
2.4
In the following sections the protocol support of the MUNICH32 is described in detail for
transmit and receive direction separately.
Each section starts with a discussion of the general features proceeds with protocol
variants and options from the channel specification and closes with a description of the
interrupts and special topics.
HDLC
Transmit Direction General Features
In transmit direction
– the starting and ending flag (7E
– the interframe time-fill between frames
– the zero insertions (a ‘0’-bit after 5 consecutive ‘1’s inserted within a frame)
– (optional) the Frame Check Sequence (FCS) at the end of a frame
is generated automatically.
Options
The different options for this mode are
– the kind of the interframe time-fill character in the channel specification
– the number of interframe time-fill characters as FNUM in the transmit descriptor. For
– the correction of the number of interframe time-fill characters by
– 7E
– FF
the values FNUM = 0, 1, 2 we have
– FNUM = 0
– FNUM = 1
– FNUM = 2
zero insertions by programming FA in the channel specification.
– FA = 0:
– FA = 1:
H
H
Detailed Protocol Description
for IFTF = 0
for IFTF = 1
frame 1, 7E
frame 1, 7E
frame 1, 7E
FNUM from the transmit descriptor is taken directly to determine
the number of interframe time-fill characters as shown in Figure 39.
FNUM from the transmit descriptor is reduced by
number of the zero insertions of the frame corresponding to the
transmit descriptor as shown in Figure 40. This allows for a more or
less constant bit rate transmission for long HDLC frames.
H
H
H
, frame 2 (start flag = end flag)
, 7E
, IC, 7E
H
before and after a frame)
H
, frame 2
H
, frame 2
76
Functional Description
1
/
1
8
/
8
of the number of
of the
PEB 20320
01.2000