Parallax / Scenix / UBICOM SX28AC/DP-G 75MHz uC Microcontroller, RARE

Description

New, genuine Parallax SX28AC/DP Microcontrollers
These microcontrollers have been discontinued and are no longer available. Once they're gone, they're gone! They are still widely supported, with sites like sxlist.com dedicated to the SX line. There is also the SX/B compiler (free!), which makes programming easy in BASIC language. I can provide links if you ask, eBay won't allow them in this listing.
75 MIPS Performance
SX20AC/SX28AC: DC - 75 MHz
SX20AC/SX28AC: as low as 13.3 ns instruction cycle, 39.9 ns internal interrupt response
1 instruction per clock for most instructions (skips require 2 clocks, branches require 3 clocks, IREAD requires 4)
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, RISC-like instruction set
All non-branch instructions are single cycle
Eight-level push/pop hardware stack for subroutine operation
Fast table lookup capability through run-time readable code (IREAD instruction)
Totally predictable program execution rate for precise 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 interrupt response time
External wakeup/interrupt capability on Port B (8 pins)
Flexible I/O
All port 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 output pins 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 programmable 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
Programming and Debugging Support
On-chip in-system serial programming support via the oscillator pins
On-chip in-system debugging support logic
Real-time emulation, full program debug, and integrated development environment offered by the Parallax SX-Key® programming device
The language options available: Parallax Assembly; Parallax SX/B (BASIC); and CCS SX/C
Software Support
Native assembly instruction set
Expanded assembly instruction set available in the SASM assembler of the Parallax SX-Key IDE
Parallax SX/B compiler (BASIC)
Several “C” compliers available from third-party vendors