peb20534 Infineon Technologies Corporation, peb20534 Datasheet - Page 176

• Manufacturer Part Number: peb20534
• Description: Dma Supported Serial Communication Controller With 4 Channels
• Manufacturer: Infineon Technologies Corporation

PEB 20534
PEF 20534
Detailed Protocol Description
Note: The SCC does not check whether the length of the frame, i.e. the number of bytes,
to be transmitted makes sense according the HDLC protocol or not.
8.1.6
Procedural Support (Layer-2 Functions)
When operating in the auto mode, the SCC offers a high degree of protocol support. In
addition to address recognition, the SCC autonomously processes all (numbered) S- and
I-frames (window size 1 only) with either normal or extended control field format
(modulo-8 or modulo-128 sequence numbers – selectable via register CCR1 bit ’MCS’).
The following functions will be performed:
– updating of transmit and receive counter
– evaluation of transmit and receive counter
– processing of S commands
– flow control with RR/RNR
– generation of responses
– recognition of protocol errors
– transmission of S commands, if acknowledgement is not received
– continuous status query of remote station after RNR has been received
– programmable timer/repeater functions.
In addition, all unnumbered frames are forwarded directly to the processor. The logical
link can be initialized by software at any time (Reset HDLC Receiver by RRES command
in register CMDR).
Additional logical connections can be operated in parallel by software.
Data Sheet
176
2000-05-30