INTRODUCTION

1.2 MSM80C154S/MSM83C154S Features

Full static circuitry

Internal program memory (ROM)

16384 words 8 bits (MSM83C154S)

External program memory (ROM) Connectable up to 64K bytes

Internal data memory (RAM)

256 words 8 bits

External data memory (RAM) Connectable up to 64K bytes

Four sets of working registers (R0 thru R7 4)

Stack

Free use of 256-word 8-bit internal data memory area

Four input/output ports (8-bit 4)

Serial ports (UART operation)

Six types of interrupts

(1)Two external interrupts

(2)Three timer interrupts

(3)One serial port interrupt

*Priority allocated interrupt processing

*Multi-level interrupt processing by software management

CPU power down function

(1)Idle mode: CPU stopped while oscillation continued. (Software setting)

(2)PD mode: CPU and oscillation all stopped.

(Software setting)

(Setting I/O ports to floating status possible)

(3)HPD mode: CPU and oscillation all stopped.

(Hardware setting)

(Setting I/O ports to floating status possible)

CPU power down mode cancellation

(1)Execution commenced from address 0 by CPU resetting. (IDLE, PD, and HPD mode cancellation)

*RESET pin is used

(2)Execution from interrupt address by interrupt request, or execution resumed from next address after the stop address. (IDLE and PD mode cancellation)

*External, timer, and serial port interrupts

I/O control registers (0F8H)

b0: Port 0, 1, 2, and 3 floating setting (PD, HPD)

b1: Port 1 high impedance input port setting

b2: Port 2 high impedance input port setting

b3: Port 3 high impedance input port setting

b4: Port 1, 2, and 3 pull-up resistance switching (10 kW pull-up resistance switch off to leave only 100 kW)

b5: Serial port reception error detector bit

b6: 32-bit timer mode setting (TL0+TH0+TL1+TH1)

5

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Sonic Alert msm83c154s, msm80154s, msm85c154hvs user manual MSM80C154S/MSM83C154S Features