General Description
The ASM0402C is very low cost voice synthesizer with 4-bit microprocessor. It has various features including 4-bit ALU, ROM, RAM, I/O ports, timers, clock generator, watchdog timer(WDT), voice synthesizer, etc. It consists of 22 instructions in the device. With CMOS technology and halt function can minimize power dissipation. Its architecture is similar to RISC, with two stages of instruction pipeline. It allows all instructions to be executed in a single cycle, except for program branches and data table read instructions (which need two instruction cycles).

Feature
◆ Single power supply can operate from 2.4V through 5V
◆ Internal Program ROM: 2K x 10-bit
◆ 1 sets of 14-bit DPR can access up to 16K x 10 bits data memory space
◆ Data Registers:
    • 48 x 4-bit data RAM (00-1Fh plus 40h-4Fh)
    • Unbanked special function registers (SFR) range: 20h-3Fh
◆ I/O Ports:
    • PRA: 2-bit I/O Port A (2Bh)
◆ On-chip clock generator: Resistive Clock Drive(RM)
◆ Timer: 1
    • Timer0: a 9-bit auto-reload timer/counter
◆ Stack: 2-level subroutine nesting
◆ HALT and Release from HALT function to reduce power consumption
◆ Watch Dog Timer (WDT)
◆ Instruction: 1-cycle instruction except for table read and program branches which are 2-cycles
◆ Number of instruction: 22
◆ The Voice function can be implemented by microprocessor instruction
    • One 8-bit COUT output for ASMxxxxx