The HT66FB540, HT66FB550 and HT66FB560 are Flash Memory A/D with USB type 8-bit high performance RISC architecture microcontrollers, designed for applications that interface directly to analog signals and which require an USB interface. Offering users the convenience of Flash Memory multi-programming features, these devices also include a wide range of functions and features. Other memory includes an area of RAM Data Memory.

Analog features include a multi-channel 12-bit A/D converter and dual comparator functions. Multiple and extremely flexible Timer Modules provide timing, pulse generation and PWM generation functions. Communication with the outside world is catered for by including fully integrated SPI, I2C and USB interface functions, three popular interfaces which provide designers with a means of easy communication with external peripheral hardware. Protective features such as an internal WatchdogTimer, Low Voltage Reset and Low Voltage Detector coupled with excellent noise immunity and ESD protection ensure that reliable operation is maintained in hostile electrical environments. The external interrupt can be triggered with falling edges or both falling and rising edges.

A full choice of four oscillator functions are provided including two fully integrated system oscillators which requires no external components for their implementation. The ability to operate and switch dynamically between a range of operating modes using different clock sources gives users the ability to optimize microcontroller operation and minimize power consumption.

The inclusion of flexible I/O programming features, Time-Base functions along with many other features ensure that these devices will find specific excellent use in a wide range of application possibilities such as sensor signal processing, motor driving, industrial control, consumer products, subsystem controllers, etc. These devices are fully supported by the Holtek range of fully functional development and programming tools, providing a means for fast and efficient product development cycles.

CPU Features

• Operating voltage:
  •  VDD (MCU):
    •     fSYS =4MHz/6MHz: 2.2V~5.5V
    •     fSYS =12MHz: 2.7V~5.5V
  •  VDD (USB mode):
    •     fSYS =6MHz/12MHz: 3.3V~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
• Four oscillators
  • External Crystal -- HXT
  • External 32.768kHz Crystal -- LXT (Only
  •      available in HT66FB540/550/560)
  • Internal RC -- HIRC
  • Internal 32kHz RC -- LIRC
• Multi-mode operation: NORMAL, SLOW, IDLE and SLEEP
• All instructions executed in one or two instruction cycles
• Table read instructions
• 62 powerful instructions
• Up to 12-level subroutine nesting
• Bit manipulation instruction

Peripheral Features

• Flash Program Memory: 4Kx16~16Kx16
• RAM Data Memory: 256x8~1024x8
• USB 2.0 Full Speed compatible
• Up to 8 endpoints supported including endpoint 0
• All endpoints except endpoint 0 can support interrupt and bulk transfer
• All endpoints except endpoint 0 can be configured as 8, 16, 32, 64 bytes FIFO size
• Endpoint 0 support control transfer
• Endpoint 0 has 8 byte FIFO
• Support 3.3V LDO and internal UDP 1.5kW pull-up resistor
• Internal 12MHz RC OSC with 0.25% accuracy for all USB modes
• Watchdog Timer function
• Up to 45 bidirectional I/O lines
• Dual pin-shared external interrupts
• Multiple Timer Modules for time measurement, input capture, compare match output or PWM output or single pulse output function
  • - 2 Compact type 10-bit Timer Modules - CTM
  • - 1 Standard type 10-bit Timer Module - STM
  • - 1 Standard type 16-bit Timer Module - STM
• Serial Interface Modules with Dual SPI and I2C interfaces
• Single Serial Peripheral Interface - SPIA
• Up to Dual Comparator functions
• Dual Time-Base functions for generation of fixed time interrupt signals
• Up to 16 channel 12-bit resolution A/D converter
• Low voltage reset function
• Low voltage detect function
• Flash program memory can be re-programmed up to 10,000 times
• Flash program memory data retention > 10 years
• Support In Application Programming function - IAP
• Support In System Programing function -  ISP
• Wide range of available package types 

Specification:

• max. frequency: 16MHz
• VDD: 2.2V~5.5V
• program memory: 4Kx16
• data memory: 512x8
• stack: 8
• I/O: 25
• timer: 10-bit CTM×2, 10-bit STM×1, 16-bit STM×1
• ADC: 12-bitx8
• comparator: 2
• interface: SPI/I²C×1, SPI×1
• case: 28SSOP