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SX20AC/SX28AC

1.2 Key Features

50 MIPS Performance
· SX20AC/SX28AC: DC - 75 MHz
· SX20AC/SX28AC: 13.3 ns instruction cycle, 39.9 ns in-

ternal interrupt response

· 1 instruction per clock (branches 3)

EE/FLASH Program Memory and SRAM Data Memory
· Access time of < 13.3 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
· 20-pin SSOP, 28-pin 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