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13-22 March, 2003 Developer’s Manual
Intel
®
80200 Processor based on Intel
®
XScale
™
Microarchitecture
Software Debug
13.11.6 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.
A Capture_DR loads TXRXCTRL[31] into DBG_SR[0]. The other bits in DBG_SR are loaded as
shown in Figure 13-4.
The captured data is scanned out during the Shift_DR state.
Care must be taken while scanning in data. While polling TXRXCTRL[31], incorrectly setting
DBG_SR[35] or DBG_SR[1] may cause unpredictable behavior following an Update_DR.
Update_DR parallel loads DBG_SR[35:1] into DBG_REG[34:0]. Whether the new data gets
written to the RX register or an overflow condition is detected depends on the inputs to the RX
write logic.
Figure 13-4. DBGRX Hardware
12
3334
TDOTDI
DBG_SR
Capture_DR
Update_DR
DBG_REG
1233435
delay
031
software read
TXRXCTRL
RX
TCK
Intel
®
80200 Processor
software read/write
0
0
0
0
1
3031 29
RX
DBG_REG[1]
Write
Logic
Flush RR
to TXRXCTRL[29]
TXRXCTRL[31]
set TXRXCTRL[31]
clear by SW read from RX
set by Debugger Write
clear DBG_REG[34]
undefined
enable
set overflow
CLK