PEB20534H-10V2.1 Infineon Technologies, PEB20534H-10V2.1 Datasheet - Page 182

• Manufacturer Part Number: PEB20534H-10V2.1
• Description: Communication Controller 208-Pin FQFP
• Manufacturer: Infineon Technologies

Protocol Error Handling:
Depending on the error type, erroneous frames are handled according to table 25.
Table 25
Frame Type Error Type
I
S
Note: The station variables ( V(S), V(R) ) are not changed.
8.1.8
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 CCR1 register of the corresponding channel.
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
– external timer mode
– same transmit and receive addresses, since only responses can be transmitted, i.e.
Data Sheet
Register CCR1 bit fields MDS1, MDS0, ADM = ‘000’
Register TIMR bit TMD = ‘0’
Register XADR bit fields XAD1 = XAD2 and register RADR bit fields RAL1 = RAL2
(address of secondary).
Half-Duplex SDLC-NRM Operation
Error Handling
CRC error
aborted
unexpec. N(S)
unexpec. N(R)
CRC error
aborted
unexpec. N(R)
with I-field
Generated
Response
–
–
S-frame
–
–
–
–
–
182
Detailed Protocol Description
Generated
Interrupt
FI (from DMAC)
FI (from DMAC)
–
PCE
–
–
PCE
PCE
Rec. Status
CRC error
abort
–
–
–
–
–
–
PEB 20534
PEF 20534
2000-05-30