GENERAL DESCRIPTION
CTM8B5X series is an EPROM based 8-bit microcontroller which employs a full CMOS technology enhanced with low-cost, high speed and high noise immunity. Watchdog Timer, RAM, EPROM, tri-state I/O port, power down mode, and real time programmable clock/counter are integrated into this chip. CTM8B5X contains 33 instructions, all are single cycle except for program branches which take two cycles.
On chip memory is available with 512x14 bits of EPROM for CTM8B54E/55E, 1Kx14 bits of EPROM for CTM8B56E, 2Kx14 bits of EPROM for CTM8B57E and 24 to 72 bytes of static RAM.

FEATURES
• Total of 33 single word instructions .
• The fast execution time may be 200ns for all single
   cycle instructions under 20MHz operating.
• Operating voltage range: 2.3V ~ 6.5V
• 8-bit data bus.
• 14-bit instruction word.
• Four-level stacks.
• On chip EPROM size :
   512x14 bits for CTM8B54E/55E,
   1Kx14 bits for CTM8B56E,
   2Kx14 bits for CTM8B57E.
• Internal RAM size : 25 bytes for CTM8B54E/56E, 24 bytes for CTM8B55E,
• 72 bytes for CTM8B57E.
• Direct and indirect addressing modes for data accessing
• 8-bit real time clock/counter with 8-bit programmable prescaler.
• Internal power-on Reset.
• Device Reset Timer.
• Code protection.
• Sleep mode for power saving.
• On chip Watchdog Timer(WDT) based on internal RC oscillator.
• Three I/O ports PA, PB nad PC with independent direction control.
• 4 types of oscillator can be selected by code options:
   - RC : Low-cost RC oscillator
   - XTAL : Standard crystal oscillator
   - HFXTAL : High frequency crystal oscillator
   - LFXTAL : Low frequency crystal oscillator