TXC-05802AIPQ Transwitch Corporation, TXC-05802AIPQ Datasheet - Page 28

• Manufacturer Part Number: TXC-05802AIPQ
• Manufacturer: Transwitch Corporation

Specifications of TXC-05802AIPQ

• Operating Supply Voltage (typ): 3.3/5V
• Operating Temperature Classification: Industrial
• Package Type: PQFP
• Mounting: Surface Mount
• Pin Count: 208
• Lead Free Status / Rohs Status: Not Compliant

Translation Record Formats
VPI Translation Record Formats
VPI translation records are four bytes long if TRHENA=0, or six bytes long if TRHENA=1, as shown in
Figure 20. Each VPI may be either idle or busy. If it is busy, then each VPI may be set for VPI-only translation,
or for combined VPI/VCI translation. The control bits (A, P, E and I) and Routing Headers are described in the
preceding sections.
The calculation of the start address for the VP record when there is no Tandem Routing Header (control bit
TRHENA=0) is performed as follows:
If TRHENA=1 then:
3
2
1
0
3
2
1
0
3
2
1
0
VPI and VCI Translation,
TRHENA=0
Idle VPI, TRHENA=0
VPI Translation, TRHENA=0
CellBus Bus Routing Header MSB
CellBus Bus Routing Header LSB
A
A
1
0
A
1
P
X
P
0
1
P
VCI Page Offset
E
E
X
E
E
E
VPI, 8 LSB
1/0
1/0
1/0
I
I
I
VCI Page Size
VPI, 4 MSB
Figure 20. VPI Translation Record Formats
5
4
3
2
1
0
5
4
3
2
1
0
5
4
3
2
1
0
VPI Translation, TRHENA=1
VPI and VCI Translation,
TRHENA=1
Idle VPI, TRHENA=1
CellBus Bus Routing Header MSB
CellBus Bus Routing Header LSB
A
A
A
1
1
0
Tandem Routing Header MSB
Tandem Routing Header LSB
P
P
P
1
X
0
VP_Start_Addr = VP# x 4
VP_Start_Addr = VP# x 6
VCI Page Offset
E
E
E
E
E
X
VPI, 8 LSB
1/0
1/0
1/0
I
I
I
VCI Page Size
VPI, 4 MSB
- 28 -
If the VPI is unused, then the MSB (Active
bit, A) of relative address zero is set to
zero, indicating idle. If a cell arrives with
this VPI number, it is discarded and is
counted as a misrouted cell.
If the VPI is busy and is to have VPI num-
ber translation only, then the A bit is set=1,
and the P bit is set=1. In this case, the VPI
to be inserted on the cell is contained in
the 4 LSB of relative address zero (4 MSB
of new VPI), and in relative address one (8
LSB of new VPI). CellBus Bus and Tandem
Routing Headers are also contained in the
next two or four bytes.
If the VPI is busy and is set for combined
VPI/VCI number translation, a reference is
generated to a VCI translation record. The
VPI is set active (A=1), and is set for VCI
translation (P=0). The 4 LSB of relative
address zero contain the VCI Page Size,
which is the number of assigned VCI
pages, each of 128, 256, 512, or 1024 VCI
records, allocated to this VPI (range from
1 to 16, where 0H=16). Relative address
one contains the VCI Page Offset, which
indicates where among the VCI pages the
first utilized page starts.
Ed. 3, November 1999
TXC-05802
CUBIT- Pro
TXC-05802-MB