Intel 80200, Processor 13.14.2 LDIC JTAG Data Register

Developer’s Manual March, 2003 13-35
Intel® 80200 Processor based on Intel® XScale™ Microarchitecture
Software Debug
13.14.2 LDIC JTAG Data Register
The LDIC JTAG Data Register is selected when the LDIC JTAG instruction is in the JTAG IR. An
external host can load and invalidate lines in the instruction cache through this data register.
The data loaded into LDIC_SR1 during a Capture_DR is unpredictable.
All LDIC functions and data consists of 33 bit packets which are scanned into LDIC_SR1 during
the Shift_DR state.
Update_DR parallel loads LDIC_SR1 into LDIC_REG which is then synchronized with the Intel®
80200 processor clock and loaded into the LDIC_SR2. Once data is loaded into LDIC_SR2, the
LDIC State Machine turns on and serially shifts the contents if LDIC_SR2 to the instruction cache.
Note that there is a delay from the time of the Update_DR to the time the entire contents of
LDIC_SR2 have been shifted to the instruction cache. Removing the LDIC JTAG instruction from
the JTAG IR before the entire contents of LDIC_SR2 are sent to the instruction cache, results in
unpredictable behavior. Therefore, following the Update_DR for the last LDIC packet, the LDIC
instruction must remain in the JTAG IR for a minimum of 15 TCKs. This ensures the last packet is
correctly sent to the instruction cache.
Figure 13-10. LDIC JTAG Data Register Hardware
TDOTDI
Capture_DR
Update_DR
12332
TCK
Intel® 80200 Processor
0
12
32 0
unpredictable
LDIC_SR1
To Instruction Cache
LDIC_REG
12
32 0
LDIC_SR2
LDIC
State Mac hine
CLK