CPU Features

Operating voltage
– VDD (MCU)
fSYS=6MHz: 2.2V~5.5V
fSYS=12MHz: 2.7V~5.5V
– VDD (USB Mode)
fSYS=6MHz/12MHz: 2.7V~5.5V
fSYS=16MHz: 4.5V~5.5V
Up to 0.25us instruction cycle with 16MHz system clock at VDD=5V
Power down and wake-up functions to reduce power consumption
Oscillator types
– External High Speed Crystal — HXT
– Internal High Speed RC — HIRC
– External 32.768kHz Crystal — LXT
– Internal 32kHz RC — LIRC
Fully integrated internal 12MHz oscillator with 0.25% accuracy for all USB modes which requires no external components
Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
All instructions executed in one to three instruction cycles
Table read instructions
115 powerful instructions
Up to 16-level subroutine nesting
Bit manipulation instruction

Peripheral Features

Program Memory: Up to 64Kx16
Data Memory: 3072×8
True EEPROM Memory: 256×8 (Only for HT66F4390)
Watchdog Timer function
Up to 36 bidirectional I/O lines
Dual external interrupt lines shared with I/O pins
Multiple Timer Modules for time measure, input capture, compare match output, PWM output function or single pulse output function
– Dual Compact type 10-bit Timer
Modules — CTM0 & CTM1
– Single Periodic type 10-bit Timer
Module — PTM
– Single Standard type 16-bit Timer
Module — STM
Smart Card interface compatible with and certifiable to the ISO 7816-3 Standards
1.8V, 3V, 5V smart card supply
Dual Serial SPI Interfaces — SPI0 & SPI1
Single I2C interface
Dual Fully-duplex Universal Asynchronous Receiver and Transmitter Interface — UART0 & UART1
Dual comparator functions
Dual Time-Base functions for generation of fixed time interrupt signals
8-channel 12-bit resolution A/D converter
In Application Programming function — IAP
In System Programming function — ISP
Low voltage reset function
Low voltage detect function
Flash program memory can be re-programmed up to 100,000 times
Flash program memory data retention > 10 years
True EEPROM data memory can be re-programmed up to 1,000,000 times (Only for HT66F4390)
True EEPROM data memory data retention > 10 years (Only for HT66F4390)
Package types: 48-pin LQFP, 64-pin LQFP