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Boundary Scan Test Interface
25-16
Élan™SC520 Microcontroller User’s Manual
all test data registers retain their previous state. When JTAG_TMS is High and a rising
edge is applied to JTAG_TCK, the controller moves to the Select-DR state.
25.4.3.1.3
Select-Data Register (DR)-Scan State
This is a temporary controller state. The test data register selected by the current instruction
retains its previous state. If JTAG_TMS is held Low and a rising edge is applied to
JTAG_TCK when in this state, the controller moves into the Capture-DR state and a scan
sequence for the selected test data register is initiated. If JTAG_TMS is held High and a
rising edge is applied to JTAG_TCK, the controller moves to the Select-IR-Scan state.
The instruction does not change in this state.
25.4.3.1.4
Capture-DR State
In this state, the Boundary Scan register captures input pin data if the current instruction
is EXTEST or SAMPLE/PRELOAD. The other test data registers, which do not have parallel
input, are not changed.
The instruction does not change in this state.
When the TAP controller is in this state and a rising edge is applied to JTAG_TCK, the
controller enters the Exit1-DR state if JTAG_TMS is High, or the Shift-DR state if JTAG_TMS
is Low.
25.4.3.1.5
Shift-DR State
In this controller state, the test data register connected between JTAG_TDI and JTAG_TDO
as a result of the current instruction shifts data one stage toward its serial output on each
rising edge of JTAG_TCK.
The instruction does not change in this state.
When the TAP controller is in this state and a rising edge is applied to JTAG_TCK, the
controller enters the Exit1-DR state if JTAG_TMS is High, or remains in the Shift-DR state
if JTAG_TMS is Low.
25.4.3.1.6
Exit1-DR State
This is a temporary state. While in this state, if JTAG_TMS is held High, a rising edge
applied to JTAG_TCK causes the controller to enter the Update-DR state, which terminates
the scanning process. If JTAG_TMS is held Low and a rising edge is applied to JTAG_TCK,
the controller enters the Pause-DR state.
The test data register selected by the current instruction retains its previous value during
this state. The instruction does not change in this state.
25.4.3.1.7
Pause-DR State
The pause state allows the test controller to temporarily halt the shifting of data through
the test data register in the serial path between JTAG_TDI and JTAG_TDO. An example
of using this state could be to allow a tester to reload its pin memory from disk during
application of a long test sequence.
The test data register selected by the current instruction retains its previous value during
this state. The instruction does not change in this state.
The controller remains in this state as long as JTAG_TMS is Low. When JTAG_TMS goes
High and a rising edge is applied to JTAG_TCK, the controller moves to the Exit2-DR state.
Содержание Elan SC520
Страница 1: ...lan SC520 Microcontroller User s Manual Order 22004A...
Страница 4: ...iv lan SC520 Microcontroller User s Manual...
Страница 28: ...Introduction xxviii lan SC520 Microcontroller User s Manual...
Страница 42: ...Architectural Overview 1 14 lan SC520 Microcontroller User s Manual...
Страница 78: ...System Initialization 3 22 lan SC520 Microcontroller User s Manual...
Страница 108: ...Clock Generation and Control 5 10 lan SC520 Microcontroller User s Manual...
Страница 118: ...Reset Generation 6 10 lan SC520 Microcontroller User s Manual...
Страница 148: ...System Arbitration 8 24 lan SC520 Microcontroller User s Manual...
Страница 214: ...SDRAM Controller 10 36 lan SC520 Microcontroller User s Manual...
Страница 230: ...Write Buffer and Read Buffer 11 16 lan SC520 Microcontroller User s Manual...
Страница 288: ...GP Bus DMA Controller 14 22 lan SC520 Microcontroller User s Manual...
Страница 316: ...Programmable Interval Timer 16 8 lan SC520 Microcontroller User s Manual...
Страница 328: ...Software Timer 18 4 lan SC520 Microcontroller User s Manual...
Страница 346: ...Real Time Clock 20 12 lan SC520 Microcontroller User s Manual...
Страница 360: ...UART Serial Ports 21 14 lan SC520 Microcontroller User s Manual...
Страница 414: ...AMDebug Technology 26 8 lan SC520 Microcontroller User s Manual...