Overview
The LC66556B and LC66558B are four-bit single-chip CMOS microcontrollers that integrate on a single chip all the functions required in a microcontroller, including ROM, RAM, I/O ports, two serial interfaces, comparator inputs, three-value inputs, timers and interrupts. These products are provided in a 64-pin package.
These products differ from the earlier LC66558A Series in the power supply voltage range and certain other electrical characteristics.

Features and Functions
• On-chip ROM and RAM with 6 k (or 8 k) byte and 512 × 4-bit capacities
• The same instruction set (with 127 instructions) as the LC66000 Series (except that the SB instruction is not supported)
• I/O ports: 54 pins
• 8-bit serial interface: two circuits (16-bit cascade connection supported)
• Instruction cycle: 0.92 to 10 µs (at 3 to 5.5 V)
• Powerful timers and prescalers 12-bit timer: time-limit timer, event counter, pulse width measurement, square wave output 8-bit timer: time-limit timer, event counter, PWM output, square wave output 12-bit prescaler: time base functions
• Powerful 11-factor 8-vector interrupt system External interrupts: 6 factors/3 vectors Internal interrupts: 5 factors/5 vectors
• Flexible I/O functions Comparator inputs, three-value inputs, 20 mA drive outputs, 15 V breakdown voltage pins, pull-up/opendrain option switching possible
• Runaway detection function (watchdog timer) option
• 8-bit I/O function
• Power saving functions: halt and hold modes Package: DIP64S, QFP64E
• Evaluation LSI: LC66599 (evaluation chip) + EVA850/800-TB665XX LC66E516 (On-chip EPROM microcontrollers) LC66P516 (On-chip OTPROM microcontrollers)