PMC-Sierra, Inc.
PM5356
S/UNI-622-MAX
DATASHEET
S/UNI-622-MAX
PMC-1980589
ISSUE 5
SATURN USER NETWORK INTERFACE (622-MAX)
Pin Name
Type
Pin
No.
Function
RENB
Input
N23
The UTOPIA receive read enable (RENB) is used to initiate
reads from the receive FIFO. The system may de-assert RENB
if it is unable to accept more data.
In 16-bit Level 2 ATM mode, a read is not performed and
RDAT[15:0], RPRTY and RSOC will tristate when RENB is
sampled high. When RENB is sampled low, the word on the
RDAT[15:0] bus is read from the receive FIFO and changes to
the next value on the next clock cycle.
In 8-bit Level 3 ATM mode, a read is not performed and
RDAT[7:0] does not change when RENB is sampled high.
When RENB is sampled low, the word on the RDAT[7:0] bus is
read from the receive FIFO and changes to the next value on
the next clock cycle.
RENB is sampled on the rising edge of RFCLK.
RCA
Output
N20
The UTOPIA receive cell available (RCA) provides direct status
indication of when a cell is available in the receive FIFO.
In 16-bit Level 2 mode, RCA can be configured to de-assert
when either zero or four bytes remain in the FIFO. RCA will thus
transition low on the rising edge of RFCLK after payload word 24
or 19 is output on the RDAT[15:0] bus depending on the RXCP
registers.
In 8-bit Level 3 mode, RCA is ignored as the RVAL signal
identifies valid data on the RDAT[7:0] bus.
RCA is updated on the rising edge of RFCLK.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
29
PMC [ PMC-SIERRA, INC ]
