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RAPIDUS for XL Computers

RAPIDUS for XL Computers

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765.45 PLN

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Weight: 0.2 kg

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Internal accelarator for 8bit ATARI XE series. 


  • internal CPU turbo card for Atari 800 XL machines (dedicated apater included),
  • WDC 65C816 microprocessor operating at 20 MHz!!!
  • managed by Xilinx Spartan6 FPGA and XC95XL CPLD devices,
  • 1024kb of zero waitstate SRAM,
  • up to 30.5MB of storage ram - SDRAM clocked at 160 MHz!!!
  • 512kB of Flash memory (256kB is reserved for FPGa cores, 256kB for OS and New Device handler)
  • 256b of EEPROM,
  • high speed bus connector for external I/O interfaces, DMA support,
  • working modes, fully software controlled
  • low power consumption due to DC/DC converters, no extra power supply required
  • on screen bios menu, accesible by pressing INV ( and hold) + RESET 



RAPIDUS UPGRADE may be very problematic with ULTIMATE 1MB upgrade or VBXE....

but.... i have observed that majority of problems are gone,when You replace orginal DRAM



I presume dram triming were crucial, thus SRAM module as it depends only on O2 and RV signal actually,

eliminates ram access glitches. / 2022-02-10/






  • RAPIDUS board
  • ADAPTUS board (adapter to fix in 800xl - check last video)
  • 3pin molex connector



  • If you are not familiar with soldering or you do not have proper tools, please LET a pro technician do it for you or send me your ATARI BOARD for installation. Contact me to arrange installation.
  • Please remeber - wrong tools usage or low skills may damage atari and ultimate; any damage/harm to your hardware is NOT subject of any kind of warranty.
  • Installation is easy, but unexperienced hands can do a lot of damage. Please, do not ask me questions WHAT HAVE I DONE WRONG WITH INSTALLATION - answer will be always the same - I DO NOT KNOW






Product gallery



 Main features: 

  • ULTIMATE friendly connection - look at video at bottom of this page
  • 2 pcbs - one cpu adapter and ROM adapter connected with 16pin flat cable





  • if Your CPU is NOT socketed, desolder it carefully, then solder in its place  "ADAPTUS 800XL 6502C SIDE" with bottom socket
  • if Your CPU is socketed, remove it from socket carefully, insert  " ADAPTUS 800XL 6502C SIDE" without bottom socket (orginal ATARI  sockets removal and usage of supplied precision ones along with supplied adapters STRONGLY SUGGESTED)



  • if Your ROM is NOT socketed, desolder it carefully, then solder in its place  "ADAPTUS 800XLRAPIDUS SIDE" with bottom socket
  • if Your ROM is socketed, remove it from socket carefully, insert  "ADAPTUS 800XL RAPIDUS SIDE"  without bottom socket (orginal ATARI  sockets removal and usage of supplied precision ones along with supplied adapters STRONGLY SUGGESTED)



  • Connect two adapter with supplied flat cable ( WARNING ! PIN 1 must pin connected to PIN 1, etc..)
  • Insert PROPERLY desoldered/removed CPU and ROM back into sokcets at "ADAPTUS 800XL RAPIDUS SIDE"
  • If ATARI doesn`t start - please check Your WORK ONCE AGAIN




  • Remove cpu from socket and insert it to RAPIDUS
  • Insert RAPIDUS into CPU SOCKET


STEP FIVEmake connections  to rapidus plug:

  • Power off Atari


for atari 800XL without freddy chip 

  • EXTSEL - 9 pin of 74ls08  
  • MPD  - 14 pin of MMU
  • GND - example - pin 7 of 74ls08


for atari 800XL with freddy chip:

  • GND – example – Freddie CHIP pin 20
  • EXTSEL – Freddie pin 3
  • MPD – MMU pin 14


  • power ON ATARI



  • on some ataris below patch has to be applied 


  •  O2 signal pull down - in case, when Your rapidus have problems with core loading (progress bar stops), please, make another patch: solder 3kOhm resistor between 74LS08 pin 1 (o2) and pin 7 (Gnd)