General Description
The APU4003 is a single chip 4-bit micro-controller with LCD drivers. It can drive up to 3 common times or 25 segments, i.e. a 75-segment LCD driver. This 4-bit micro-controller contains a 4-bit parallel processing ALU, 1024x15-bit program ROM, 64x4-bit data RAM, input/output ports, alarm driver, timer, clock generator, crystal and RC oscillator circuit, LCD driver and 79 powerful instructions in a single chip. The HALT instruction can be used to stop all internal operations other than timer, clock generator, crystal/RC oscillator and LCD driver. Very low current dissipation can be easily achieved by combining 4 kinds of interrupt functions and HALT instruction to minimize the operation cycle.

Features
• Very low current dissipation
• Wide operating voltage range
• Supports both Ag and Li batteries
• Powerful instruction set
• 4-level subroutine nesting (including interrupt)
• 4 event driven interrupts, 2 external and 2 internal
• ROM size: 1024x15 bits
• RAM size: 64x4 bits
• Input ports: 2 ports/8 pins (S and M)
• Output port: 1 port/4 pins (P)
• Pseudo serial output port (P)
• Input/output ports: 2 ports/8 pins (I/OA and I/OB)
• Control outputs: ALARM, LIGHT
• LCD driver outputs (can drive up to 75 LCD segments)
• Mask option to select 4 LCD drive modes: static, duplex (1/2 duty 1/2 bias, 1/3 duty 1/2 bias or 1/3 duty 1/3 bias)
• Mask option permits LCD driver output pins to be used for DC output ports; up to 25 pins are available
• Segment PLA circuit permits any layout on LCD panel
• Built-in clock generator (crystal or RC)
• Built-in voltage doubler, halver, tripler