Boundary Scan Test Interface
Élan™SC520 Microcontroller User’s Manual
25-15
Figure 25-4
Test Access Port Controller State Diagram
25.4.3.1
TAP Controller States
25.4.3.1.1
Test-Logic-Reset State
In this state, the test logic is disabled so that normal operation of the device can continue
unhindered. This is achieved by initializing the Instruction register such that the IDCODE
instruction is loaded. No matter what the original state of the controller, the controller enters
Test-Logic-Reset state when the JTAG_TMS input is held High (1) for at least five rising
edges of JTAG_TCK. The controller remains in this state while JTAG_TMS is High. The
TAP controller is also forced to enter this state when JTAG_TRST is asserted.
The JTAG TAP controller is not reset as a function of PWRGOOD when the system is
powered up. Rather, JTAG_TRST has an internal pulldown resistor which causes the TAP
controller to reset.
25.4.3.1.2
Run-Test-Idle State
This is a controller state between scan operations. When in this state, the controller remains
in this state as long as JTAG_TMS is held Low. For instructions not causing functions to
execute during this state, no activity occurs in the test logic. The Instruction register and
Test-Logic-Reset
Run-Test/Idle
0
Select-DR-Scan
0
Capture-DR
0
1
Exit1-DR
0
Pause-DR
1
1
Update-DR
0
0
Shift-DR
Exit2-DR
0
1
1
0
Select-IR-Scan
0
Capture-IR
0
1
Exit1-IR
0
Pause-IR
1
1
Update-IR
0
0
Shift-IR
Exit2-IR
0
1
1
0
1
0
1
1
1
1
1
JTAG_TRST
Содержание Elan SC520
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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...