¡ Semiconductor
MSM80C48/49/50, MSM80C35/39/40
Details of IC pin status as a result of executing the FLT instruction are shown in the above table.
(4) FLTT (floating of all output pins)
Instruction code :
Description :
1
1
0
0
0
0
1
0
Internal ROM mode
Floating
External ROM mode
Operation
ALE
PSEN
PROG
WR
Floating
Operation
Floating
Floating
Floating
Floating
PD
Floating
Floating
T0 OUT
P1
Floating
Floating
Floating
Floating
Floating
P20-3 operation
Operation
P2
BP
Floating
XTAL
Operation
Operation
Details of IC pin status as a result of executing the FLTT instruction are shown in above
Table.
Example 1 : Power-down mode accomplished by stopping oscillation.
m Can be set by execution of HLTS [82H] instruction.
Example 2 : Power-down mode accomplished by stopping the clock supply to the CPU
control circuit.
m Can be set by execution of HALT [01H] instruction.
Example 3 : Power-down mode by floating of P1 - , P2 - and BP - , and subsequent
0 7
0 7
0 7
stopping of CPU oscillation.
m Can be set by first executing the FLT [A2H] instruction, followed by the
HLTS [82H] instruction.
Example 4 : Power-down mode by floating P1 - , P2 - and BP - , and then stopping the
0 7
0 7
0 7
clock supply to the CPU control circuit.
m Can be set by first executing the FLT [A2H] instruction, and then the HALT
[01H] instruction.
Example 5 : Power-downmodebyfloatingalloutputpins,followedbystoppingoscillation.
m Can be set by first executing the FLTT [C2H] instruction followed by
execution of the HLTS [82H] instruction.
Example 6 : Power-down mode by floating all output pins, followed by stopping of the
clock supply to the CPU control circuit.
m Can be set by first executing the FLTT [C2H] instruction, followed by
execution of the HALT [01H] instruction. Connect the pull-up resistor or
pull-down resistor to port pin and fix the output port pin level to either 1or
0 when output port is set to floating.
16/20
OKI [ OKI ELECTRONIC COMPONETS ]
