PEF81902FV1.1 Lantiq, PEF81902FV1.1 Datasheet - Page 111

• Manufacturer Part Number: PEF81902FV1.1
• Manufacturer: Lantiq

Specifications of PEF81902FV1.1

• Lead Free Status / RoHS Status: Supplier Unconfirmed

– RPF (Receive Pool Full) interrupt, indicating that a data block of the selected length
– RME (Receive Message End) interrupt, indicating that the reception of one message
– RFO (Receive Frame Overflow) interrupt, indicating that a complete frame could not
There are two control commands that are used with the reception of data:
– RMC (Receive Message Complete) command, telling the T-SMINT
– RRES (Receiver Reset) command, resetting the HDLC receiver and clearing the
Note: The significant interrupts and commands are underlined as only these are usually
The following description of the receive FIFIO operation is illustrated in
RFIFO block size (threshold) of 16 and 32 bytes.
The RFIFO requests service from the microcontroller by setting a bit in the ISTAH
register, which causes an interrupt (RPF, RME, RFO). The microcontroller then reads
status information (RBCH,RBCL), data from the RFIFO and changes the RFIFO block
size (EXMR.RFBS). A block transfer is completed by the microcontroller via a receive
message complete (CMDR.RMC) command. This causes the space of the transferred
bytes being released for new data and in case the frame was complete (RME) the reset
of the receive byte counter RBC (RBCH,RBCL).
The total length of the frame is contained in the RBCH and RBCL registers which contain
a 12 bit number (RBC11...0), so frames up to 4095 byte length can be counted. If a frame
is longer than 4095 bytes, the RBCH.OV (overflow) bit will be set. The least significant
1)
Data Sheet
(EXMR.RFBS) can be read from RFIFO. The message which is currently received
exceeds the block size so further blocks will be received to complete the message.
has been completed and the message has been stored in the RFIFO.
Either
– a short message has been received
– the last part of a long message has been received
be stored in RFIFO and is therefore lost as the RFIFO is occupied. This occurs if the
host fails to respond quick enough to RPF/RME interrupts since previous data was not
read by the host.
block has been read from the RFIFO and the corresponding FIFO space can be
released for new receive data.
receive FIFO of any data (e.g. used before start of reception). It has to be used after
a change of the message transfer mode. RRES does not clear pending interrupt
indications of the receiver, but have to be be cleared by reading these interrupts.
If RMC is omitted, then no new interrupt can be generated.
(message length
(message length
used during a normal reception sequence.
the defined block size (EXMR.RFBS)
the defined block size (EXMR.RFBS)).
97
1)
Functional Description
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Figure 43
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PEF 81902
2001-11-12
for a