16/20

¡ 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 :

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.

stopping of CPU oscillation.

m

Can be set by first executing the FLT [A2H] instruction, followed by the

HLTS [82H] instruction.

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-down mode by floating all output pins, followed by stopping oscillation.

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.

11000010

ALE

P2

XTAL

Internal ROM mode

Floating

Floating

Operation

External ROM mode

Operation

Operation

PSEN

Floating

Operation

PROG

Floating

Floating

WR

Floating

Floating

PD

Floating

Floating

T0 OUT

Floating

Floating

P1

Floating

Floating

BP

Floating

Operation