INTRODUCTION
The ST72F521 and ST72521B devices are members of the ST7 microcontroller family designed for mid-range applications with a CAN bus interface(Controller Area Network).
All devices are based on a common industry standard 8-bit core, featuring an enhanced instruc tion set and are available with FLASH or ROM program memory.

■ Memories
   – 32K to 60K dual voltage High Density Flash (HDFlash) or ROM with read-out protection capability. In-Application Programming and In-Circuit Programming for HDFlash devices
   – 1K to 2K RAM
   – HDFlash endurance: 100 cycles, data retention: 20 years at 55°C
■ Clock, Reset And Supply Management
   – Enhanced low voltage supervisor (LVD) for main supply and auxiliary voltage detector (AVD) with interrupt capability – Clock sources: crystal/ceramic resonator os cillators, internal RC oscillator and bypass for external clock
   – PLL for 2x frequency multiplication
   – Four power saving modes: Halt, Active-Halt, Wait and Slow
■ Interrupt Management
   – Nested interrupt controller
   – 14 interrupt vectors plus TRAP and RESET
   – Top Level Interrupt (TLI) pin
   – 15 external interrupt lines (on 4 vectors)
■ Up to 64 I/O Ports
   – 48 multifunctional bidirectional I/O lines
   – 34 alternate function lines
   – 16 high sink outputs
■ 5 Timers
   – Main Clock Controller with: Real time base, Beep and Clock-out capabilities
   – Configurable watchdog timer
   – Two 16-bit timers with: 2 input captures, 2 output compares, external clock input on one timer, PWM and pulse generator modes – 8-bit PWM Auto-Reload timer with: 2 input captures, 4 PWM outputs, output compare and time base interrupt, external clock with event detector
■ 4 Communications Interfaces
   – SPI synchronous serial interface
   – SCI asynchronous serial interface
   – I2C multimaster interface (SMbus V1.1 compliant)
   – CAN interface (2.0B Passive)
■ Analog periperal (low current coupling)
   – 10-bit ADC with 16 input robust input ports
■ Instruction Set
   – 8-bit Data Manipulation
   – 63 Basic Instructions
   – 17 main Addressing Modes
   – 8 x 8 Unsigned Multiply Instruction
■ Development Tools
   – Full hardware/software development package
   – In-Circuit Testing capability