PEB22554 Datasheet, PDF (171/397 Pages) Siemens Semiconductor Group – ICs for Communications

PEB 22554
RDO…
CRC16…
RAB…
Operational Description E1
– a frame which is too short taking into account the operation mode
selected via MODE (MDS2-0) and the selection of receive CRC
ON/OFF (CCR2.RCRC) as follows:
• MDS2-0 = 011 (16 bit Address),
RCRC = 0 : 4 bytes; RCRC = 1 : 3-4 bytes
• MDS2-0 = 010 (8 bit Address),
RCRC = 0 : 3 bytes; RCRC = 1 : 2-3 bytes
Note: Shorter frames are not reported.
Receive Data Overflow
A RFIFO data overflow has occurred during reception of the frame.
Additionally, an interrupt can be generated (refer to
ISR1.RDO/IMR1.RDO).
CRC16 Compare/Check
0… CRC check failed; received frame contains errors.
1… CRC check o.k.; received frame is error-free.
Receive Message Aborted
The received frame was aborted from the transmitting station.
According to the HDLC protocol, this frame must be discarded by the
receiver station.
HA1, HA0…
High Byte Address Compare
Significant only if 2-byte address mode has been selected.
In operating modes which provide high byte address recognition, the
QuadFALC compares the high byte of a 2-byte address with the
contents of two individually programmable registers (RAH1, RAH2)
and the fixed values FE_H and FC_H (broadcast address).
Dependent on the result of this comparison, the following bit
combinations are possible:
00… RAH2 has been recognized
01… Broadcast address has been recognized
10… RAH1 has been recognized C/R = 0 (bit 1)
11… RAH1 has been recognized C/R = 1 (bit 1)
Note: If RAH1, RAH2 contain identical values, a match is indicated
by ‘10’ or ‘11’.
Semiconductor Group
171
09.98