D-20 M68060 USER’S MANUAL MOTOROLA
LPSTOP Low-Power Stop LPSTOP
(MC68060, MC68LC060, MC68EC060)
3. At the time of the bus cycle termination, (TA or TEA) the state of bus grant
determines how the processor will leave the system bus while in the low-power
stopped state. If the processor is granted the bus, it will drive the transfer
attributes, address bus, data bus, and most control signals high while in the
low-power stopped state. If the bus grant is removed from the processor, it will
threestate all threestateable signals of the system bus at the conclusion of the
bus write broadcast cycle.
4. After the broadcast cycle is complete the processor will load the immediate
operand into the SR and drive the PST lines signalling the low-power stopped
state has been entered.
5. Once the low-power stopped state has been entered, the internal processor
clock is disabled (except to a small number of flip flops to support interrupt and
reset recognition) and all input signals except the RSTI and IPLx, may float.
The processor clock (CLK) input may be stopped during the low-power
stopped state for additional power saving. If this is done, CLK must be stopped
in the low state.
6. During entry into the low-power stopped state, the system bus must be quies-
cent from the cycle after the broadcast cycle termination until the PST signals
indicate the low-power stopped state. During exit from the low-power stopped
state, the system bus must be quiescent and control signal inputs to the pro-
cessor negated, beginning with the cycle RSTI, or IPLx is asserted until the
PST signals indicate that the processor is in an exception processing state.
Set according to the immediate operand.
Immediate field—Specifies the data to be loaded into the status register.
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0