TRS-80_MiSTer

Model I Support

port of HT1080Z by Jozsef Laszlo to MiSTer renamed TRS-80 after new cassette loading from dshadoff and CMD loading from steddyman

rename the ht1080z folder TRS-80 on the MiSTer SD Card if you have it already

Mist homepage: http://joco.homeserver.hu/fpga/mist_ht1080z_en.html

To learn how to use the TRS-80, this is a quick tutorial: https://www.classic-computers.org.nz/system-80/driving_instructions.htm

To load a cassette game:

  return
  system
  <Then go to the OSD and load a cassette>
  [type the first letter of the file you want to load (e or g for the disk images provided)]
  / 

To load a CMD file:

just select it in the OSD. Some CMD files won't work if they access disk rom routines. Sometimes a clean reboot is necessary before loading a CMD.

Features:

• Simulates a TRS-80 Model I with 48KB installed (currently no expansion interface or disk drives)
• Sound output is supported (however cassette saving sound is suppressed)
• Cassette loading is many times faster than the original 500 baud

Notes:

• The included BOOT.ROM has been modified to take advantage of a special interface for loading cassettes; original BASIC ROMs are also supported

Technical:

Special ports (i.e. Z-80 "OUT"/"IN" commands) have been added as follows:

• VIDEO:

  • OUT 0, n (where n=(0-7)) -> change foreground color
  • OUT 1, n (where n=(0-7)) -> change bacgronund color
  • OUT 2, n (where n=(0-7)) -> change overscan color

• Memory-mapped cassette:

  • OUT 6, n (where n=(0-255)) -> set address bits 23-16 of virtual memory pointer
  • OUT 5, n (where n=(0-255)) -> set address bits 15- 8 of virtual memory pointer
  • OUT 4, n (where n=(0-255)) -> set address bits 7- 0 of virtual memory pointer
  • A = INP(4) -> read virtual memory at current virtual memory pointer and increment pointer
  • Note that cassette image is loaded at 0x010000, and no memory exists beyond 0x01ffff