TXC-04251AIPQ Transwitch Corporation, TXC-04251AIPQ Datasheet - Page 42

• Manufacturer Part Number: TXC-04251AIPQ
• Manufacturer: Transwitch Corporation

Specifications of TXC-04251AIPQ

• Pin Count: 160
• Screening Level: Industrial
• Package Type: PQFP
• Lead Free Status / Rohs Status: Not Compliant

TXC-04251-MB
Ed. 4, March 2000
QT1M
TXC-04251
POINTER LEAK RATE CALCULATIONS
Notes:
1. The procedure described in Notes 2 through 8 below must be performed independently for each of the four ports of the
2. The procedure shown in the diagram above uses a ten-second sliding window with a resolution of one second.
3. The initial FIFO Leak Rate Register value (in memory map address 49H, 79H, A9H, or D9H) must first be set to 01 Hex
4. Measure ten consecutive one-second samples from the Positive and Negative Stuff Counters being used. Store all ten dif-
5. Calculate the leak rate (L.R.) using the following equation:
6. Set the FIFO Leak Rate Register (address 49H, 79H, A9H, or D9H) with the value between 1 and 255 calculated above,
7. Recalculate the value of 'C' by subtracting the oldest sample and adding the newest, and calculate a new leak rate, as
8. Continue to repeat the steps described in Notes 5, 6 and 7 until AIS, LOP , LOS or NDF is received or until you reset the
QT1M device.
(reset value).
ference values, i.e.,
There are eight pairs of stuff counters in the QT1M; care should be taken to use the pair appropriate to the programmed
configuration of the device. The counters are located at addresses 32H, 62H, 92H and C2H (for the A-Side) and 3C, 6C,
9C, and CC (for the B-Side).
then take another one-second sample (e.g., S11).
described in Note 5 (e.g., using S2 through S11).
QT1M.
L.R. = Hex [ Int [ 1180 / C ] ], where
C = ABS [ S1 + S2 + ... + S10 ].
Then, if L.R. < 1, let L.R = 1,
or if L.R. > 255, let L.R = 255.
S
S2 = POS STUFF COUNT2 - NEG STUFF COUNT2, and so on through
S10 = POS STUFF COUNT10 - NEG STUFF COUNT10.
1
= POS STUFF COUNT1 - NEG STUFF COUNT1,
Start
Leak Rate
to 01 Hex
Set FIFO
(Note 3)
AIS, LOP
LOS, NDF
or RESET
DATA SHEET
Add Newest
Subt Oldest
1 Second,
Measure
add to C
(Note 4)
(Note 7)
10 SEC
- 42 -
10 SEC
Leak Rate
Leak Rate
1 Second
Calculate
Set FIFO
Measure
(Note 5)
(Note 6)
(Note 6)
FIFO