
TABLE 8. Header / Trailer Usage
(Continued)
Function
Use Instruction Header
Use Instruction Trailer
Use both Instruction Header and Trailer
Use Data Header
Use Data Trailer
Use both Data Header and Trailer
Reserved
Bit 2
0
0
0
1
1
1
1
Bit 1
0
1
1
0
0
1
1
Bit 0
1
0
1
0
1
0
1
TABLE 9. Macro Type bits 10 and 11
Bit 1
0
0
1
1
Bit 0
0
1
0
1
Function
BIST Macro
Shift Macro
Function
Loop on loop bit for Vector count. No Data
Loop on loop bit for vector count. Read data from TDO_SM memory
Loop on loop bit for vector count. Read data from TDO_SM memory
Do not loop on loop bit of macro. No data to be shifted
Shift Macro with Capture
State Macro
TABLE 10. Sequencer Structure
Bit(s)
Function
Sequence repeat count (up to 255)
Vector repeat count
Vector number
Repeat vector repeat count and vector number
Vector repeat count (up to 255)
Vector number (up to 63)
0x00 - 0x1F
0x20 - 0x2F
0x30 - 0x3F
..x.. - ..x..
0x3E0 - 0x3EF
0x3F0 - 0x3FF
TABLE 11. Scan Bridge Support Structure
Bit(s)
Function
Levels of Scan Bridge support to be inserted in the scan chain
Hierarchical Level 0 Scan Bridge Address
Hierarchical Level 0 Scan Bridge LSP
Hierarchical Level 1 Scan Bridge Address
Hierarchical Level 1 Scan Bridge LSP
Hierarchical Level Scan Bridge Address and LSP
Hierarchical Level 125 Scan Bridge Address
Hierarchical Level 125 Scan Bridge LSP
0x00 - 0x0F
0x10 - 0x17
0x18 - 0x1F
0x20 - 0x27
0x28 - 0x2F
..x.. - ..x..
0x7F0 - 0x7F7
0x7F8 - 0x7FF
Module Descriptions
Figure 1
shows a high level view of the STA101 which is
composed of two main modules, the Parallel Processor In-
terface (PPI) and the Serial Scan Interface (SSI) which
interface to each other through a dual-port memory. The PPI
provides a parallel interface for transferring data into and out
of the dual-port memory, and for configuring, controlling and
obtaining the status of the device. The SSI which resides on
the other side of the dual-port memory provides the parallel-
to-serial and serial-to-parallel conversion paths for providing
test data and test control to support the ScanMaster and
IEEE 1532 functions.
Dual Port Memory
The dual port memory will be treated as a separate module
in the design to facilitate portability of the RTL of the design
to an FPGA host. The Dual Port Memory module is a 2048 x
32 bit dual-port memory which acts as the buffer between
the PPI and the SSI. There are seven regions of memory as
viewed from the processor side. These regions, shown in
Table 4
, are TDO_SM, TDI_SM, Expected, Mask, Vector,
Header/Trailer, Macro. Sequencer, and ScanBridge Support.
Each has a pointer which resides in the PPI.
The memory is big endian oriented and is viewed as a single
entity from the SSI side and the SSI maintains a pointer. The
dual port memory module does not include any logic outside
of its own macro function, so all the timing and support logic
is included in the following PPI and SSI sections. There will
be no logic included in the STA101 design to utilize the
"busy" indicators to keep the user from overwriting memory
locations. The only area were this could occur in memory
would be the TDI_SM memory space since both the SSI and
PPI can write to this space, but the drivers shouldn’t allow
PPI writes to this area during normal operations.
S
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