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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Intel XScale
®
Processor
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
128
Order Number: 306262-004US
A Capture_DR loads the TX register value into DBG_SR[34:3] and TXRXCTRL[28] into
DBG_SR[0]. The other bits in DBG_SR are loaded as shown in
.
The captured TX value is scanned out during the Shift_DR state.
Data scanned in is ignored on an Update_DR.
A ‘1’ captured in DBG_SR[0] indicates the captured TX data is valid. After doing a
Capture_DR, the debugger must place the JTAG state machine in the Shift_DR state to
guarantee that a debugger read clears TXRXCTRL[28].
3.6.11.5
DBGRX JTAG Command
The ‘DBGRX’ JTAG instruction selects the DBGRX JTAG data register. The JTAG op code
for this instruction is ‘0b00010’. Once the DBGRX data register is selected, the
debugger can send data to the debug handler through the RX register.
3.6.11.6
DBGRX JTAG Register
The DBGRX JTAG instruction selects the DBGRX JTAG Data register. The debugger uses
the DBGRX data register to send data or commands to the debug handler.
Figure 15.
DBGTX Hardware
B4341-01
TDO
TDI
DBG_SR
Capture_DR
Update_DR
1
2
3
34
35
0
31
TXRXCTRL
TX
Core CLK
software read-only
0
0
0
1
28
set by SW write to TX
clear by Debugger read
Ignored
software write
TCLK
delay
0x0000 0000
1
0