TXC-04222-AIOG Transwitch Corporation, TXC-04222-AIOG Datasheet - Page 89

• Manufacturer Part Number: TXC-04222-AIOG
• Manufacturer: Transwitch Corporation

Specifications of TXC-04222-AIOG

• Screening Level: Industrial
• Package Type: BGA
• Lead Free Status / Rohs Status: Not Compliant

POINTER LEAK RATE CALCULATIONS
The Pointer Leak Rate register for each channel is 10 bits long (X+017H and X+018H for the A side, and
X+067H and X+088H for the B side). The host processor must write the first eight bits (X+017H and X+067H)
followed by the remaining two bits of the 10 bit register. If the pointer Leak Rate Register is set to 000H the
receive FIFO in the Desynchronizer is bypassed.
Notes:
1. The procedure described in Notes 3 through 8 below must be performed independently for each of the 28 channels in the TEMx28.
2. The procedure shown in the diagram above uses a thirty-second sliding window with a resolution of one second. When
3. The FIFO Leak Rate Register must first be set to a value of 13, (00DH) for DS1 or 10, (00AH) for E1.
4. Measure thirty consecutive one-second samples from the Positive and Negative Stuff Counters being used. Store all
5. Calculate the leak rate:
6. Set the FIFO Leak Rate Register with the value between 1 and 1023, (3FFH) calculated above, then take another
7. Recalculate the value of ’C’, ‘D’, ‘E’, ‘F’ and ‘G’ by discarding the oldest value and adding the newest value (i = i + 1).
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 channel or
When both buses are used, the Leak Rate must be calculated independently for each bus. The following notes describe
the actions for one channel on one bus.
implementing the Pointer Leak Rate Calculation, while gathering the data from the previous One Second Counter, the
PM1S clock and microprocessor read should be synchronized.
thirty difference values, i.e.,
Care should be taken to use the pair appropriate to the programmed configuration of the device.
Leak Rate = The smaller of 1023, (3FFH) or (Hex[INT{3300/C}], Hex[INT{500/D}] if D > 2, Hex[INT{375/E}] if E > 2,
Hex[INT{250/F}] if F > 2, Hex[INT{125/G}] if G > 2) where Hex is the hexadecimal value, INT is the integer value:
C = Absolute Value [sum(S
F = Absolute Value [sum(S
loop shown in the diagram (notes 5, 6 and 7). If the C is 0, 1, 2 or 3 set the Leak Rate to 1023, (3FFH). A pointer will be
leaked before another arrives for uniform pointer arrivals. If D, E, F, or G > 2, faster pointer leaking accounts for a rapid
change in pointer arrival rate (e.g., start up).
one-second sample (e.g., S
restart the device.
S
S
S
1
2
30
= POS STUFF COUNT
= POS STUFF COUNT
= POS STUFF COUNT
Proprietary TranSwitch Corporation Information for use Solely by its Customers
i
29+i
to S
31
).
to S
30+i
1
2
Start
30
- NEG STUFF COUNT
- NEG STUFF COUNT
Leak Rate
Set FIFO
(Note 3)
)], D = Absolute Value [sum(S
30+i
- NEG STUFF COUNT
)], G = Absolute Value [S
Power On,
AIS, LOP,
LOS, NDF,
or RESET
DATA SHEET
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1
2
,
, and so on through
30
Add Newest
Subt Oldest
add to sum
< 30 SEC
.
1 Second
Measure
(Note 7)
(Note 4)
30+i
27+i
] and i represents the number of times through the
to S
30+i
30 SEC
)], E = Absolute Value [sum(S
Leak Rate
Leak Rate
Calculate
1 Second
Set FIFO
Measure
(Note 5)
(Note 6)
(Note 6)
FIFO
TXC-04222-MB, Ed. 6
TXC-04222
28+i
TEMx28
to S
June 2003
30+i
)],