
PM7346 S/UNI-QJET
DATASHEET
PMC-960835
ISSUE 6
SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND ITS CUSTOMERS’ INTERNAL USE
321
Figure 23
- 8-bit Wide, 53 Word Structure
Bit 0
H1
H2
H4
Bit 7
H5
PAYLOAD1
W ord 1
W ord 2
W ord 3
W ord 4
W ord 5
W ord 6
PAYLOAD48
W ord 53
H3
The 8-bit SCI-PHY compliant data structure is selected when the ATM8 input is
tied high. Bit 7 of each word is the most significant bit (which corresponds to the
first bit transmitted or received). Selection between the 52-byte and 53-byte
structures is done by the DS27_53 register bit in the S/UNI-QJET Configuration
1 register. The 52 byte structure is chosen when DS27_53 is set to logic 0. The
53 byte structure is chosen when DS27_53 is set to logic 1. The start of cell
indication input and output (TSOC and RSOC) are coincident with Word 1
(containing the first cell header octet). The header check sequence octet (HCS)
is passed through the 53 byte structure. Word 5 of this structure contains the
HCS octet.
In the receive direction, cells containing "detected and uncorrected" header
errors are dropped when the HCSPASS bit in the RXCP-50 Configuration 2
Register is set to logic zero. No HCS status information is passed within this
data structure. Cells with error free headers and "detected and corrected"
headers are passed when HCSPASS and DISCOR are logic zero. Cells
containing uncorrectable HCS errors are dropped while the HCSPASS bit is set
to logic zero. Error free headers, "detected and corrected" headers, and
"detected and uncorrected" headers are passed when HCSPASS is a logic one.