TEST FEATURES
15-9
15
15.3.5
TAP Controller
The TAP controller is a 16-state synchronous finite state machine that controls the sequence of test
logic operations. The TAP can be controlled via a bus master. The bus master can be either
automatic test equipment or a component (i.e. PLD) that interfaces to the Test Access Port (TAP).
The TAP controller changes state only in response to a rising edge of TCK or power-up. The value
of the test mode state (TMS) input signal at a rising edge of TCK controls the sequence of state
changes. The TAP controller is automatically initialized on powerup. In addition, the TAP
controller can be initialized by applying a high signal level on the TMS input for five TCK periods.
Behavior of the TAP controller and other test logic in each controller state is described in the
following subsections. For greater detail on the state machine and the public instructions, refer to
IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture Document.
idcode
IEEE 1149.1
Optional
0010
2
idcode is used in conjunction with the device identification register. It connects
the identification register between TDI and TDO in the Shift_DR state. When
selected, idcode parallel-loads the hard-wired identification code (32 bits) on
TDO into the identification register on the rising edge of TCK in the Capture_DR
state.
NOTE
: The device identification register is not altered by data being shifted in
on TDI.
bypass
IEEE 1149.1
Required
1111
2
bypass instruction selects the Bypass register between TDI and TDO pins while
in SHIFT_DR state, effectively bypassing the processor’s test logic. 0
2
is
captured in the CAPTURE_DR state. This is the only instruction that accesses
the Bypass register. While this instruction is in effect, all other test data registers
have no effect on the operation of the system. Test data registers with both test
and system functionality perform their system functions when this instruction is
selected.
runbist
i960 Jx
Processor
Optional
0111
2
runbist selects the one-bit RUNBIST register, loads a value of 1 into it and
connects it to TDO. It also initiates the processor’s built-in self test (BIST) feature
which is able to detect approximately 82% of the stuck-at faults on the device.
The processor AC/DC specifications for V
CC
and CLKIN must be met and
RESET must be de-asserted prior to executing runbist.
After loading runbist instruction code into the instruction register, the TAP
controller must be placed in the Run-Test/Idle state.
bist
begins on the first
rising edge of TCK after the Run-Test/Idle state is entered. The TAP controller
must remain in the Run-Test/Idle state until
bist
is completed. runbist requires
approximately 414,000 core cycles to complete
bist
and report the result to the
RUNBIST register’s. The results are stored in bit 0 of the RUNBIST register.
After the report completes, the value in the RUNBIST register is shifted out on
TDO during the Shift-DR state. A value of 0 being shifted out on TDO indicates
bist
completed successfully. A value of 1 indicates a failure occurred. After
bist
completes, the processor must be recycled through the reset state to begin
normal operation.
Instruction
/ Requisite
Opcode
Description
Содержание i960 Jx
Страница 1: ...Release Date December 1997 Order Number 272483 002 i960 Jx Microprocessor Developer s Manual ...
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Страница 25: ...1 INTRODUCTION ...
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Страница 35: ...2 DATA TYPES AND MEMORY ADDRESSING MODES ...
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Страница 47: ...3 PROGRAMMING ENVIRONMENT ...
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Страница 73: ...4 CACHE AND ON CHIP DATA RAM ...
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Страница 85: ...5 INSTRUCTION SET OVERVIEW ...
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Страница 111: ...6 INSTRUCTION SET REFERENCE ...
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Страница 195: ...INSTRUCTION SET REFERENCE 6 83 6 Opcode mov 5CCH REG movl 5DCH REG movt 5ECH REG movq 5FCH REG See Also LOAD STORE lda ...
Страница 233: ...7 PROCEDURE CALLS ...
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Страница 257: ...8 FAULTS ...
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Страница 291: ...9 TRACING AND DEBUGGING ...
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Страница 309: ...10 TIMERS ...
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Страница 325: ...11 INTERRUPTS ...
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Страница 369: ...12 INITIALIZATION AND SYSTEM REQUIREMENTS ...
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Страница 413: ...13 MEMORY CONFIGURATION ...
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Страница 429: ...14 EXTERNAL BUS ...
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Страница 469: ...15 TEST FEATURES ...
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Страница 493: ...A CONSIDERATIONS FOR WRITING PORTABLE CODE ...
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Страница 503: ...B OPCODES AND EXECUTION TIMES ...
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Страница 515: ...C MACHINE LEVEL INSTRUCTION FORMATS ...
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Страница 523: ...D REGISTER AND DATA STRUCTURES ...
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Страница 551: ...GLOSSARY ...
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Страница 561: ...INDEX ...
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