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STANDARD PRODUCT
PM8315 TEMUX
DATASHEET
PMC-1981125
ISSUE 7
HIGH DENSITY T1/E1 FRAMER WITH
INTEGRATED VT/TU MAPPER AND M13 MUX
PROPRIETARY AND CONFIDENTIAL
197
When the FIFO fill level is exceeded, an interrupt is generated. The FIFO must
be emptied to remove this source of interrupt.
The RDLC can be used in a polled or interrupt driven mode for the transfer of
frame data. In the polled mode, the processor controlling the RDLC must
periodically read the RDLC Status register to determine when to read the RDLC
Data register. In the interrupt driven mode, the processor controlling the RDLC
uses the TEMUX INTB output and the TEMUX Master Interrupt Source registers
to determine when to read the RDLC Data register.
In the case of interrupt driven data transfer from the RDLC to the processor, the
INTB output of the TEMUX is connected to the interrupt input of the processor.
The processor interrupt service routine verifies what block generated the
interrupt by reading the TEMUX Master Interrupt Source register followed by one
of the second level master interrupt source registers to identify one of the 29
HDLC receivers as the interrupt source. Once it has identified that the RDLC
has generated the interrupt, it processes the data in the following order:
1. Read the RDLC Status register. The INTR bit should be logic 1.
2. If OVR = 1, then discard the last frame and go to step 1. Overrun causes a
reset of FIFO pointers. Any packets that may have been in the FIFO are lost.
3. If COLS = 1, then set the EMPTY FIFO software flag.
4. If PKIN = 1, increment the PACKET COUNT. If the FIFO is desired to be
emptied as soon as a complete packet is received, set the EMPTY FIFO
software flag. If the EMPTY FIFO software flag is not set, FIFO emptying will
delayed until the FIFO fill level is exceeded.
5. Read the RDLC Data register.
6. Read the RDLC Status register.
7. If OVR = 1, then discard last frame and go to step 1. Overrun causes a reset
of FIFO pointers. Any packets that may have been in the FIFO are lost.
8. If COLS = 1, then set the EMPTY FIFO software flag.
9. If PKIN = 1, increment the PACKET COUNT. If the FIFO is desired to be
emptied as soon as a complete packet is received, set the EMPTY FIFO
software flag. If the EMPTY FIFO software flag is not set, FIFO emptying will
delayed until the FIFO fill level is exceeded.
10. Start the processing of FIFO data. Use the PBS[2:0] packet byte status bits
to decide what is to be done with the FIFO data.