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PEB 20542
PEF 20542
Programming
Data Sheet
261
2000-09-14
ASYNC, BISYNC
’
RPF
’
(Receive Pool Full) interrupt, indicating that a specified number of bytes (refer
to register
CCR3H
, bit field
’
RFTH(1..0)
’
) 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
CCR3L
.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
(
CMDRH
.RFRD).
In addition to every received character the assigned status information Parity bit (0/1),
Parity Error (yes/no), Framing Error (yes/no, ASYNC only!) is optionally stored in RFIFO.
With an end condition (
’
TCD
’
interrupt or after
’
RFRD
’
command) the length of the last
received data block is stored in register
RBCL
. The number of bytes to read from RFIFO
is determined by the 1, 2, 4 or 5 least significant bits of register
RBCL
, depending on the
selected RFIFO threshold (bit field
’
RFTH(1..0)
’
in register
CCR3H
).
Note: (For all serial modes) After the received data has been read from the RFIFO, this
must be explicitly acknowledged by the CPU issuing an
’
RMC
’
(Receive Message
Complete) command. The CPU has to handle the
’
RPF
’
interrupt before the
complete 2 x 32-byte FIFO is filled up with receive data which would cause a
“
Receive Data Overflow
”
condition.
The data reception sequence, from the CPU
’
s point of view, is outlined in
Figure 60
.
Table 16
Status Information
Length of received message
CRC result (good/bad)
Valid frame (yes/no)
ABORT sequence recognized (yes/no)
Data overflow (yes/no)
Results from address comparison
(with automatic address handling)
Type of frame (COMMAND/RESPONSE)
(with automatic address handling)
Type of Signaling Unit
(in SS7 mode)
Status Information after RME interupt
Location
registers
RBCH
,
RBCL
RSTA
register (or last byte of received data)
RSTA
register (or last byte of received data)
RSTA
register (or last byte of received data)
RSTA
register (or last byte of received data)
RSTA
register (or last byte of received data)
RSTA
register (or last byte of received data)
RSTA
register (or last byte of received data)