AN2074 Freescale Semiconductor / Motorola, AN2074 Datasheet - Page 31

• Manufacturer Part Number: AN2074
• Description: DSP56300 JTAG Examples
• Manufacturer: Freescale Semiconductor / Motorola

JTAG_EXTEST_SEQ:
START
JTAG_EXTEST:
3.9 Daisy Chain Example
The daisy chain example shows how to use the IDCODE instruction in a daisy chain configuration. Two
DSPs are daisy chained as shown in Figure 6. To read the IDCODE of the second DSP, the first DSP in the
chain must be placed in the BYPASS mode. The Select-IR scan path is selected to shift in the BYPASS
and IDCODE instructions by sending 1111 0010 on
instruction is concatenated with the IDCODE instruction. Next, the Select-DR scan path is selected to shift
out the 32-bit contents of the second DSP’s ID Register in addition to the first DSP’s 1-bit content of the
Bypass Register on
most significant byte is stored in the low byte of x:JTAG_OUT and the lower 24 bits are stored in
x:JTAG_OUT+1 as shown in Table 15. Table 14 lists the instructions used in Example 17.
org
dc
dc
dc
dc
dc
dc
dc
dc
dc
dc
dc
org
...
jsr
jsr
jsr
debug
move
jsr
rts
B3
0
0
0
0
0
0
0
1
x:
$30
$30
$10
$10
$04
$04
$04
$24
$30
$10
$00
p:$100
JTAG_RTI
JTAG_SAMPLE
JTAG_EXTEST
#JTAG_EXTEST_SEQ,r0
JTAG_EXECUTE
B2
0
0
0
1
1
1
1
1
TDO
; go to Select DR
; go to Select IR
; go to Capture IR
; go to Shift IR
; go to Shift IR - 0
; go to Shift IR - 0
; go to Shift IR - 0
; go to Exit IR
; go to Update IR
; go to Run-Test-Idle
; EXIT
Freescale Semiconductor, Inc.
. The ID Register content is stored in x:JTAG_OUT and x:JTAG_OUT+1. The
B1
0
0
1
0
0
1
1
1
For More Information On This Product,
Table 14. Daisy Chain Example Instructions
B0
0
1
0
0
1
0
1
1
Example 16. EXTEST Example
Go to: www.freescale.com
DSP56300 JTAG Examples
- 0
EXTEST
SAMPLE/PRELOAD
IDCODE
HIGHZ
CLAMP
ENABLE_ONCE
DEBUG_REQUEST
BYPASS
Instruction
TDI
least significant bit first. The BYPASS
Boundary-Scan Register
Boundary-Scan Register
ID Register
Bypass
Bypass
OnCE Register
OnCE Register
Bypass
Register Selected
Daisy Chain Example
31