© 2000 Scenix Semiconductor, Inc. All rights reserved. - 3 - www.scenix.com SX18AC/SX20AC/SX28AC/SX18AC75/SX20AC75/SX28AC75 1.2    Key Features 50 MIPS Performance
•    SX18AC/SX20AC/SX28AC: DC - 50 MHz operation       SX18AC75/SX20AC75/SX28AC75: DC - 75 MHz
•    SX18AC/SX20AC/SX28AC: 20 ns instruction cycle,       60 ns internal interrupt response
      SX18AC75/SX20AC75/SX28AC75: 13.3 ns instruction
      cycle, 39.9 ns internal interrupt response
•    1 instruction per clock (branches 3) EE/FLASH Program Memory and SRAM Data Memory
•    Access time of < 10 ns provides single cycle access
•    EE/Flash rated for > 10,000 rewrite cycles
•    2048 Words EE/Flash program memory
•    136x8 bits SRAM data memory CPU Features
•    Compact instruction set
•    All instructions are single cycle except branch
•    Eight-level push/pop hardware stack for subroutine       linkage
•    Fast table lookup capability through run-time readable       code (IREAD instruction)
•    Totally predictable program execution flow for hard real-time applications Fast and Deterministic Interrupt
•    Jitter-free 3-cycle internal interrupt response
•    Hardware context save/restore of key resources such       as PC, W, STATUS, and FSR within the 3-cycle inter-
      rupt response time
•    External wakeup/interrupt capability on Port B (8 pins) Flexible I/O
•    All pins individually programmable as I/O
•    Inputs are TTL or CMOS level selectable
•    All pins have selectable internal pull-ups
•    Selectable Schmitt Trigger inputs on Ports B, and C
•    All outputs capable of sourcing/sinking 30 mA
•    Port A outputs have symmetrical drive
•    Analog comparator support on Port B (RB0 OUT, RB1       IN-, RB2 IN+)
•    Selectable I/O operation synchronous to the oscillator clock Hardware Peripheral Features
•    One 8-bit Real Time Clock/Counter (RTCC) with pro-       gramable 8-bit prescaler
•    Watchdog Timer (shares the RTCC prescaler)
•    Analog comparator
•    Brown-out detector
•    Multi-Input Wakeup logic on 8 pins
•    Internal RC oscillator with configurable rate from 31.25       kHz to 4 MHz
•    Power-On-Reset Packages
•    18-pin SOP/DIP, 20-pin SSOP, 28-pin SOP/DIP/SSOP Programming and Debugging Support
•    On- chip in-system programming support with serial       and parallel interfaces
•    In-system serial programming via oscillator pins
•    On-chip in-System debugging support logic
•    Real-time emulation, full program debug, and integrat- ed development environment offered by third party tool
vendors