Boundary-Scan Architecture
B-6
ADSP-BF537 Blackfin Processor Hardware Reference
The
EXTEST
instruction allows internal data to be driven to the boundary
outputs and external data to be captured on the boundary inputs.
a
To protect the internal logic when the boundary outputs are over-
driven or signals are received on the boundary inputs, make sure
that nothing else drives data on the processor’s output pins.
SAMPLE/PRELOAD – Binary Code 10000
The
SAMPLE/PRELOAD
instruction performs two functions and selects the
Boundary-Scan register to be connected between
TDI
and
TDO
. The
instruction has no effect on internal logic.
The
SAMPLE
part of the instruction allows a snapshot of the inputs and
outputs captured on the boundary-scan cells. Data is sampled on the ris-
ing edge of
TCK
.
The
PRELOAD
part of the instruction allows data to be loaded on the device
pins and driven out on the board with the
EXTEST
instruction. Data is pre-
loaded on the pins on the falling edge of
TCK
.
BYPASS – Binary Code 11111
The
BYPASS
instruction selects the
BYPASS
register to be connected to
TDI
and
TDO
. The instruction has no effect on the internal logic. No data
inversion should occur between
TDI
and
TDO
.
Boundary-Scan Register
The boundary-scan register is selected by the
EXTEST
and
SAMPLE/PRELOAD
instructions. These instructions allow the pins of the processor to be con-
trolled and sampled for board-level testing.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...