
SAB 82532/SAF 82532
Operational Description
Semiconductor Group
109
07.96
9.3.2
Data Reception
9.3.2.1 Interrupt Mode
Also 2
×
32 byte FIFO buffers (receive pools) are provided for each channel in receive
direction.
There are different interrupt indications concerned with the reception of data:
HDLC/SDLC
RPF (Receive Pool Full) interrupt, indicating that a 32-byte block of data can be read
from RFIFO and the received message is not yet complete.
RME (Receive Message End) interrupt, indicating that the reception of one message
is completed, i.e. either
– one message with less than 32 bytes, or the
– last part of a message with more than 32 bytes
is stored in the RFIFO.
In addition to the message end (RME) interrupt the following information about the
received frame is stored by the ESCC2 in special registers and/or RFIFO:
Table 8
Status Information after RME Interrupt
Length of message (bytes)
Address combination and/or
Address field
Control field
Type of frame (COMMAND/RESPONSE)
CRC result (good/bad)
Valid frame (yes/no)
ABORT sequence recognized (yes/no)
Data overflow
ASYNC, BISYNC
RPF (Receive Pool Full) interrupt, indicating that a specified number of bytes (refer to
register RFC) can be read from RFIFO.
TCD (Termination Character Detected) interrupt, indicating that reception has been
terminated by reception of a specified character (refer to register TCR and bit
RFC:TCDE).
Additionally, the CPU can have access to contents of RFIFO without having received an
interrupt (and thereby causing TCD to occur) by issuing the RFIFO Read command
(CMDR:RFRD).
RBCH, RBCL
RSTA
RAL1
RHCR
RSTA
RSTA
RSTA
RSTA
RSTA
register
RFIFO: last byte
RFIFO
RFIFO
RFIFO: last byte
RFIFO: last byte
RFIFO: last byte
RFIFO: last byte
RFIFO: last byte