Texas Instruments TMS320C3x - Manual (Page 234)

Power Management Modes
7-50
- The interrupt service routine (ISR) must have been set up before placing
the device in IDLE2 mode, because the instruction following the IDLE2
instruction is not executed until the RETI (return from interrupt) instruction
is executed.
- When the device is in emulation mode, the H1 and H3 clocks continue to
run normally and the CPU operates as if an IDLE instruction was
executed. The clocks continue to run for correct operation of the emulator.
Delayed Branch
For correct device operation, the three instructions following a
delayed branch should not include either IDLE or IDLE2 instructions.
Figure 7–11.IDLE2 Timing
Idle 2 execution
Data
ADDR
H1
H3
CLKIN