Free HP 87 emulator for android.
  • include one quad disc HP9121 compatible disk unit (use RAW disc image) 
  • ram from 64 KB upto 2 MB (if you need more, 16 MB is possible, 8 MB for basic, 8MB for electronic disc)
  • cpu speed from x1 upto x50 (now UCSD pascal is fast enough)
  • rom drawer support (some usefull roms included)
  • external keyboard support (physical or bluetooth)
  • best with a 1280x800 android device
3 models:
  • HP87 base model : graph crt at 544x240 as the real computer
  • HP87+ : graph crt at 640x480 (roms patched)
  • HP87++ : graph crt at 1016x480 (roms patched)
  • On kitkat device, import/export directory is now /Android/data/o2s.emul.hp87/files/... instead of /go87/... on the sdcard. 
    For android older then kitkat, nothing change.
  • cpu emulated in native C code for speed up
  • sound not supported.
  • should work with at least 1024x600 screen.
 demo in standard mode
 demo in HP87++ mode (1016x480)

links : FPGA HP86BSeries80