peb20525 Infineon Technologies Corporation, peb20525 Datasheet - Page 102

• Manufacturer Part Number: peb20525
• Description: 2 Channel Serial Optimized Communication Controller For Hdlc/ppp
• Manufacturer: Infineon Technologies Corporation

Note: The broadcast address may be programmed in register
The primary station has to operate in transparent HDLC mode.
Reception of Frames:
The reception of frames functions similarly to the LAPB/LAPD operation (see
Duplex LAPB/LAPD Operation” on Page
Transmission of Frames:
The SCC does not transmit S-, or I-frames if not instructed to do so by the primary station
via an S-, or I-frame with the poll bit set.
The SCC can be told to send an I-frame issuing the transmit command ’XIF’ in register
CMDRL. The transmission of the frame, however, will not be initiated by the SCC until
reception of either an
• RR, or
• I-frame
with poll bit set (p = ‘1’).
After the frame has been transmitted (with the final bit set), the host has to wait for an
ALLS or XMR interrupt.
A secondary does not poll the primary for acknowledgements, thus timer supervision
must be done by the primary station.
Upon the arrival of an acknowledgement the SCC transmit FIFO is enabled and an
interrupt is forwarded to the host, either the
– message has been positively acknowledged (ALLS interrupt), or the
– message must be repeated (XMR interrupt).
Additionally, the on-chip timer can be used under host control to provide timer recovery
of the secondary if no acknowledgements are received at all.
Note: A secondary will transmit transparent frames only if the permission to send is
Examples:
A few examples of SCC/host interaction in the case of normal response mode (NRM)
mode are shown in
Data Sheet
required.
In this case registers
given by receiving an S-frame or I-frame with poll bit set (p = ‘1’).
Figure 51
RAL1
and
and
Figure
RAL2
102
52.
96).
are not equal.
Detailed Protocol Description
RAL2
if broadcasting is
PEB 20525
PEF 20525
2000-09-14
“Full-