The device has an internal low power consumption LXT oscillator, with which the standby current can be as low as 150nA (typ.) at an operating voltage of 3V with the Watchdog Timer and calendar remaining enabled. By adjusting the LXT oscillator precision using an external capacitor, the device can be applied for use in various power saving timer products. With regards to memory, the device has 16K×16 of Flash Program Memory, 2048 bytes of RAM Data Memory and 256×8 true EEPROM Data Memory.

The integrated A/D converter can be used to measure signals in applications which require the measurement of precise analog voltages. The device also contains circuitry to directly drive LEDs, while the SCOM LCD circuit can drive applications which require an LCD.

A selectable SPI/I2C/UART serial interface is also included as well as an additional independent SPI interface which can communicate with different external devices. With an In-Application Programming function, users are provided with a means of convenient and easy upgrades and modifications to their application programs.

The device is supplied in a 48-pin package type. For emulation, Holtek provides an OCDS EV device, the HT66V2560, to assist with rapid and efficient product development. .