The mPD754144 and 754244 are 4-bit single-chip microcontrollers with internal EEPROM for key-less entry. These devices are incorporated with 16 x 8-bit EEPROM, CPU for arithmetic operations, 4-Kbyte mask ROM to store software,128 x 4-bit RAM to store arithmetic data, and a carrier generator to easily output waveforms for infrared ray remote controllers. FEATURES • Internal EEPROM: 16 x 8 bits (data memory area) • Program memory (ROM) : 4096 x 8 bits • Data memory (static RAM): 128 x 4 bits • Instruction execution time · mPD754144 : 4 ms (system clock; at fX = 1 MHz) · mPD754244 : 0.95 ms (system clock; at fX = 4.19 MHz) • Oscillation circuit for system clock · mPD754144 : RC oscillation circuit (resistors and capacitors are external) · mPD754244 : crystal or ceramic oscillation circuit • Low voltage operation : VDD = 1.8 to 6.0 V · Can be driven by one lithium battery • MkI mode/MkII mode switching function • Timer function (4 channels) · Basic interval timer/watchdog timer : 1 channel · 8-bit timer counter : 3 channels