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10.13 JTAG PORT/OnCE MODULE INTERACTION
This subsection lists the details of the JTAG port/OnCE module interaction and TMS
sequencing required in order to achieve the communication described in
Section 10.12ÑOnCE Module Examples.
The external command controller can force the DSP56300 into debug mode by executing
the JTAG instruction DEBUG_REQUEST. In order to check that the DSP56300 has
entered debug mode, the external command controller must poll the status by reading
the OS[1:0] bits in the JTAG instruction shift register. The TMS sequencing appears in
Table 10-12.
The sequence to enable the OnCE module appears in Table 10-13.
After executing the JTAG instructions DEBUG_REQUEST and ENABLE_ONCE and
after the core status was polled to verify that the chip is in debug mode, the pipeline
saving procedure must take place. The TMS sequencing for this procedure is depicted in
Table 10-12.
Table 10-12 TMS Sequencing for DEBUG_REQUEST
Step
TMS
a
0
Run-Test/Idle
b
1
Select-DR-Scan
c
1
Select-IR-Scan
d
0
e
0
..................................................................
e
0
f
1
g
1
h
1
Select-DR-Scan
i
1
Select-IR-Scan
j
0
MOTOROLA
JTAG Port
OnCE Module
Capture-IR
Shift-IR
Shift-IR
Exit1-IR
Update-IR
Capture-IR
DSP56309UM/D
JTAG PORT/onCE MODULE INTERACTION
Idle
Idle
Idle
Idle
The status is sampled in the shifter.
Idle
The four bits of the JTAG
DEBUG_REQUEST (0111) are
shifted in while status is
Idle
Idle
Idle
The debug request is generated.
Idle
Idle
Idle
The status is sampled in the shifter.
On-Chip Emulation Module
Note
Ñ
Ñ
Ñ
shifted out.
Ñ
Ñ
10-29
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