peb20525 Infineon Technologies Corporation, peb20525 Datasheet - Page 101

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

Protocol Error Handling:
Depending on the error type, erroneous frames are handled according to
Table 14
Frame Type Error Type
I
S
Note: The station variables ( V(S), V(R) ) are not changed.
4.4.2
The LAP controllers of the two serial channels can be configured to function in a half-
duplex Normal Response Mode (NRM), where they operate as a slave (secondary)
station, by setting the NRM bit in the
In contrast to the full-duplex LAP B/LAP D operation, where the combined
(primary + secondary) station transmits both commands and responses and may
transmit data at any time, the NRM mode allows only responses to be transmitted and
the secondary station may transmit only when instructed to do so by the master (primary)
station. The SCC gets the permission to transmit from the primary station via an S-, or I-
frame with the poll bit (p) set.
The NRM mode can be profitably used in a point-to-multipoint configuration with a fixed
master-slave relationship, which guarantees the absence of collisions on the common
transmit line. It is the responsibility of the master station to poll the slaves periodically
and to handle error situations.
Prerequisite for NRM operation is:
– auto mode with 8-bit address field selected
– Register
– same transmit and receive addresses, since only responses can be transmitted, i.e.
Data Sheet
Register
Register
Half-Duplex SDLC-NRM Operation
CCR2L
TIMR3
XAD1
Error Handling
CRC error
Aborted
Unexpected N(S)
Unexpected N(R)
CRC error
Aborted
Unexpected N(R)
With I-field
=
bit ’TMD’ = ‘0’
bit fields ’MDS1’, ’MDS0’, ’ADM’ = ‘000’
XAD2
and register
CCR2L
Generated
Response
–
–
S-frame
–
–
–
–
–
RAL1
101
register of the corresponding channel.
=
RAL2
(address of secondary).
Detailed Protocol Description
Generated
Interrupt
RME
RME
–
PCE
–
–
PCE
PCE
Rec. Status
CRC error
Abort
–
–
–
–
–
–
Table
PEB 20525
PEF 20525
2000-09-14
14.