DESCRIPTION
The 4280 Group is a 4-bit single-chip microcomputer designed with CMOS technology for remote control transmitters. The 4280 Group has 7 carrier waves and enables fabrication of 8 × 7 key matrix.

FEATURES
• Number of basic instructions ............................................. 62
• Minimum instruction execution time ............................ 8.0 µs
   (at f(XIN) = 4.0 MHz, system clock = f(XIN)/8, VDD=3.0 V)
• Supply voltage ................................................. 1.8 V to 3.6 V
• Subroutine nesting ..................................................... 4 levels
• Timer
   Timer 1 ................................................................... 8-bit timer
   with a reload register and carrier wave output auto-control
   function
• Carrier wave output function (port CARR)
   f(XIN), f(XIN)/4, f(XIN)/8, f(XIN)/12
   f(XIN)/64, f(XIN)/96, “H” output fixed
• Logic operation function (XOR, OR, AND)
• RAM back-up function
• Key-on wakeup function (ports D7, E0–E2, G0–G3) ............. 8
• I/O port (ports D, E, G, CARR) .......................................... 16
• Oscillation circuit ..................................... Ceramic resonance
• Watchdog timer
• Power-on reset circuit
• Voltage drop detection circuit ......................... Typical:1.50 V

APPLICATION
   Various remote control transmitters