INTRODUCTION
The ST72T331 HCMOS Microcontroller Unit (MCU) is a member of the ST7 family. The device is based on an industry-standard 8-bit core and features an enhanced instruction set.

■ User Program Memory (OTP/EPROM): 8 to 16K bytes
■ User EEPROM: 256 bytes
■ Data RAM: 384 to 512 bytes including 256 bytes of stack
■ Master Reset and Power-On Reset
■ Low Voltage Detector (LVD) Reset option
■ Run and Power Saving modes
■ 44 or 32 multifunctional bidirectional I/O lines:
    – 15 or 9 programmable interrupt inputs
    – 8 or 4 high sink outputs
    – 8 or 6 analog alternate inputs
    – 13 alternate functions
    – EMI filtering
■ Software or Hardware Watchdog (WDG)
■ Two 16-bit Timers, each featuring:
    – 2 Input Captures 1)
    – 2 Output Compares 1)
    – External Clock input (on Timer A)
    – PWM and Pulse Generator modes
■ Synchronous Serial Peripheral Interface (SPI)
■ Asynchronous Serial Communications Interface (SCI)
■ 8-bit ADC with 8 channels 2)
■ 8-bit Data Manipulation
■ 63 basic Instructions and 17 main Addressing Modes
■ 8 x 8 Unsigned Multiply Instruction
■ True Bit Manipulation
■ Complete Development Support on DOS/WINDOWSTM Real-Time Emulator
■ Full Software Package on DOS/WINDOWSTM (C-Compiler, Cross-Assembler, Debugger)