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Using a Modern Day Hardware In Lieu of Real TRS-80 Parts

by @ 1:37 pm on May 10, 2012.
[Model I]      [Model III] Using Modern Hardware In/With a Real TRS-80     [Model 4]      [Model 4P]


Using a PC In Lieu of Real TRS-80 Parts
There are a number of solutions, both hardware and software, which will allow modern day hardware to function as a replacement for original TRS-80 hardware, or to otherwise help it along. This could take the form of having the PC act as a fake cassette player, fake disk drive, and the like. The below are some of those solutions:


Using a Composite Monitor In Lieu of a Model I Monitor
The TRS-80 was originally sold with a 13″ RCA Black and White Television with most of the guts ripped out. However, there can be times that a monitor is not available, you can build this cable to connect your Model I to a composite monitor. For instructions, visit here


Building a Replacement Model I Power Supply
It is very common today for people to have Model I power supply issues. While common wisdom says to cut open non-working supplies and check/replace the fuse, sometimes that is not possible, that is not the problem, or the individual is missing a supply altogether. Dean Bear has designed a replacement power supply for the Model I. For instructions, visit here


Using a PC In Lieu of a Cassette Recorder
Knut Roll-Lund has written a utility called PlayCAS which allows for the use of a PC as a cassette player for a TRS-80 Model I/III/4 Level I and II.
You simply connect your TRS-80 cassette input to your PC soundcard (if using a standard TRS-80 cable plug the plug that normally goes into the ‘Ear’ output of a CCR-8x into the PC’s headphone jack). When you then run the PLAYCAS utility, you can CLOAD (or SYSTEM) on the TRS-80 and feed it an emulated CAS file.
PLAYCAS supports 250 Baud (Level I), 500 Baud (Level II), and 1500 Baud (Model III) and supports SYSTEM (Machine Language), CLOAD/CSAVE (Level II BASIC), EDTASM (Editor Assembler), and Level I BASIC and Machine Language.
The main page for PLAYCAS can be found at http://home.online.no/~kr-lund/PlayCAS.htm. PLAYCAS can be downloaded from Knut’s site or directly Here


Using a PC In Lieu of a Disk Drive
Eric Rothfus has developed a hardware device called the SVD (Semi-Virtual Diskette) which is a device which emulates a floppy drive.
The SVD connects to the serial port of a PC and to the floppy drive cable on your TRS-80, download a floppy image to the SVD, and then boot that image on an actual TRS-80 as if that floppy was actually in the TRS-80′s drive.
The SVD is actually bi-directional, so you can also save from the TRS-80 onto the PC.
The SVD is based upon a PIC micro-controller along with some memory. It listens to the floppy control signals from the TRS-80 and generates the appropriate signals back, so the TRS-80 believes that it is attached to a real floppy drive. It attaches to a PC through a standard serial port, operating between 9600 and 115200 baud. Through programs running on your PC, you down/up-load the SVD and control its operation. The PC interface includes capability to read/write “standard” diskette formats.
Current features of the SVD are:
     
  • Up to three diskette images can be loaded at once (drive 0, 1, and 2) up to 256k
  • single-sided single density (SS SD)
  • double density (SS DD)
  • reading/booting the diskette image
  • writing the diskette image
  • LEDs for power, drive0/1/2, track0, and write
  • Supports Model I, III, 4, 4P and CoCo.
  • DOES NOT SUPPORT DOUBLE SIDED DISKS.

    • You can get more information on the main SVD page found at http://www.thesvd.com/svd/index.php. That site is VERY VERY detailed.


    Using an Add-In Card In Lieu of a Disk Drive
    The HxC Universal Floppy Disk Drive Emulator designed by Jean-François Del Nero, emulates a 34 pin floppy drive and treats DSK and DMK images which are stored on a SD card as actually floppy disks. To be clear, this product is designed to be mounted in/on an actual TRS-80, as a drive on the floppy cable.
    It can emulate one or two drives, and disk images are mounted using the three buttons on the lower right, which are NEXT, SELECT/EJECT, and PREVIOUS. The filenames are shown on the LCD, which comes in a variety of colors.
    Current features of the SVD are:
         
  • Shugart compatible mode supported
  • Two floppy disk drives emulation
  • 5V +/- 10% standard power floppy connector input
  • 3 LEDs (“Power LED”,”Floppy access LED”,” SDCard access LED “)
  • 3 buttons (“Next”,”Select/Eject”,”Previous”)
  • 1 audio transducer
  • 2*16 chars Alphanumerical LCD (LCD and buttons can be put on an external front panel)
  • SD Card up to 2GB / SDHC Card supported up to 32GB
  • FAT32 supported. Subdirectory and long name file supported
  • Actually supports MANY MANY different computers and formats
  • Track mode based floppy emulator (Full track pre-encoded in the HFE image file)
  • Write support: ISO MFM 256/512/1024Bytes sector write supported
    • The main page is here. The documentation can be found here and the changelog can be found here.



    Using a PC To Make/Read TRS-80 Disks
    Jens Schönfeld, through his company Individual Computers, has developed a floppy disk controller, called the Catweasel, which is designed to allow computers with PCI slots to read/write a variety of disk formats, including the TRS-80 Model I, III, and 4.
    The Catweasel cannot read or write TRS-80 disks on its own. Tim Mann, author of the XTRS emulator, wrote a set of tools which would allow the Catweasel to read and write the TRS-80 formats. His utilities include cw2dmk to read a real diskette into DMK file, dmk2cw to write a DMK file onto a real diskette, and two utilities dmk2jv3 and jv2dmk to convert between DMK format and JV1/3 format.

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