
SBI Bus Serializer ASSP Telecom Standard Product Data Sheet
Released
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2000168, Issue 5
258
RX_FI_BUSY
This bit indicates that the internal hardware is transferring data from the Receive FIFO
RAM into the Receive FIFO registers. The bit is set following a write to this register with
the RX_XFER_SYNC bit set or following a read from the PILC Receive FIFO Data Low
register.
Following an RX_XFER_SYNC write this bit need not be read by software if
the time interval to the successive Receive FIFO DATA register read is greater than
approximately 4 SYSCLK cycles.
This bit need not be read by software if the time interval between successive Receive FIFO
DATA register reads greater than approximately 3 SYSCLK cycles.
This means between a read access from the PILC Received FIFO Data Low register and a
read from the PILC Received FIFO Data High register. Note that there is no time restriction
between a read accesses from the PILC Received FIFO Data High register and a read from
the PILC Received FIFO Data Low register
RX_MSG_LVL[3:0]
This indicates the current number of messages in the Receive FIFO.
RX_MSG_LVL[3:0]
Number of Messages
0000
0
:
:
1000
8
Values greater than 1000 will not occur.
HDR_CRC_ERR
If this bit is set to a logic 1, the last message slot received was received with an errored
CRC-16 field. This bits is updated every message slot. This bit is provided as status only.
CRC_ERR
If this bit it set to ‘1’, the message at the head of the Receive FIFO has an errored CRC-16
field.
The usual sequence would be to read this register before reading the message buffer to
check if the message buffer that will be read from next has been received with a CRC error.
If a Receive FIFO Synchronization has been started the value of this bit is invalid until the
RX_XFER_SYNC operation has completed. This bit is valid when RX_FI_BUSY is a
logic 0 following a Receive FIFO Synchronization. The software must only check the
status of this bit before reading the first word of a message from the receive FIFO.