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HMS30C7202N
2004 MagnaChip Semiconductor Ltd. All Rights Reserved. Version 1.1
- 149 -
Pin Name
Internal Resistor
TCLK
Pullup
nTRST
Pulldown
TMS
Pullup
TDI
Pullup
11.3.3
Instruction Register
The instruction register is 4 bits in length.
There is no parity bit. The fixed value loaded into the instruction register during the CAPTURE-IR controller
state is: 0001.
11.3.4
Public Instructions
The following public instructions are supported:
Instruction
Binary Code
EXTEST
0000
SAMPLE/PRELOAD
0011
CLAMP
0101
HIGHZ
0111
CLAMPZ
1001
INTEST
1100
IDCODE
1110
BYPASS
1111
In the descriptions that follow,
TDI
and
TMS
are sampled on the rising edge of
TCK
and all output transitions
on
TDO
occur as a result of the falling edge of
TC
K.
EXTEST (0000)
The BS (boundary-scan) register is placed in test mode by the EXTEST instruction.The EXTEST instruction
connects the BS register between
TDI
and
TDO
.When the instruction register is loaded with the EXTEST
instruction, all the boundary-scan cells are placed in their test mode of operation.
In the CAPTURE-DR state, inputs from the system pins and outputs from the boundary-scan output cells to
the system pins are captured by the boundary-scan cells. In the SHIFT-DR state, the previously captured test
data is shifted out of the BS register via the
TDO
pin, whilst new test data is shifted in via the
TDI
pin to the BS
register parallel input latch. In the UPDATE-DR state, the new test data is transferred into the BS register
parallel output latch. Note that this data is applied immediately to the system logic and system pins. The first
EXTEST vector should be clocked into the boundary-scan register, using the SAMPLE/PRELOAD instruction,
prior to selecting EXTEST to ensure that known data is applied to the system logic.
SAMPLE/PRELOAD (0011)
The BS (boundary-scan) register is placed in normal (system) mode by the SAMPLE/PRELOAD instruction.
The SAMPLE/PRELOAD instruction connects the BS register between
TDI
and
TDO
.
When the instruction register is loaded with the SAMPLE/PRELOAD instruction, all the boundary-scan cells
are placed in their normal system mode of operation.
In the CAPTURE-DR state, a snapshot of the signals at the boundary-scan cells is taken on the rising edge of
TCK
. Normal system operation is unaffected. In the SHIFT-DR state, the sampled test data is shifted out of
the BS register via the
TDO
pin, whilst new data is shifted in via the
TDI
pin to preload the BS register parallel
input latch. In the UPDATE-DR state, the preloaded data is transferred into the BS register parallel output
latch. Note that this data is not applied to the system logic or system pins while the SAMPLE/PRELOAD