
PMC-Sierra, Inc.
PM73488 QSE
L
PMC-980616
Issue 3
5 Gbit/s ATMSwitch Fabric Element
Released
Datasheet
41
The idle cell format is shown in Table 6. The idle cell format is chosen to make the interface robust to both stuck-at
faults, as well as bridging faults on the data lines.
9
TAG_7
Routing tag 7.
10
OUTCHAN_3
Interpreted as OUTCHAN(15:12) by a QRT.
Not used by the QSE.
11
SP(1:0),
MB,
PARITY
SP(1:0) Spare bits.
MB
Mark bit: Cells that are present and have this bit
set are counted by the
INPUT_MARKED_CELL_COUNT (refer to
section 9.3.11
“INPUT_MARKED_CELLS_COUNT” on
page 99
) and
OUTPUT_MARKED_CELL_COUNT (refer to
section 9.3.12
“OUTPUT_MARKED_CELLS_COUNT” on
page 99
) counters.
P
Should be odd parity over nibbles 0 to 11.
12
OUTCHAN_2
Interpreted as OUTCHAN(11:8) by a QRT.
Not used by the QSE.
13
OUTCHAN_1
Interpreted as OUTCHAN(7:4) by a QRT.
Not used by the QSE.
14
OUTCHAN_0
Interpreted as OUTCHAN(3:0) by a QRT.
Not used by the QSE.
15
VCI_3
Interpreted as Virtual Channel Identifier (VCI)(15:12) by
a QRT.
Not used by the QSE.
16
VCI_2
Interpreted as VCI(11:8) by a QRT.
Not used by the QSE.
17
VCI_1
Interpreted as VCI(7:4) by a QRT.
Not used by the QSE.
18
VCI_0
Interpreted as VCI(3:0) by a QRT.
Not used by the QSE.
19
PTI(2:0)/CLP
Interpreted as the Payload Type Indicator (PTI) and Cell
Loss Priority (CLP) fields from the cell by a PM73487A.
Not used by the QSE.
20
SEQ_1
Interpreted as SEQ(7:4) by a QRT.
Not used by the QSE.
21
SEQ_0
Interpreted as SEQ(3:0) by a QRT.
Not used by the QSE.
22-117
Payload
Interpreted as 48 bytes of ATM cell payload by a QRT.
Not used by the QSE.
Table 6. PM73488 Mode Idle Cell Format
Nibble
Symbol
Definition
Comment
0
Pres(3:0)
Pres = 0100
b
: Cell not present.
1
IDLE_0
IDLE_0 = 0000
b
: All 0.
2
IDLE_1
IDLE_1 = 1000
b
: Marching 1 pattern, which protects
against bridging faults.
Table 5. Regular Cell Format (Continued)
Nibble
Symbol
Definition
Comment