FORTH Language
I downloaded a very good FORTH language interpreter and modified the code so it would correctly work with the Space-Time Productions SBC. It assumes the following:

• Ram from $8000 thru $FFFF
• SIO Channel A for normal communications thru Hyperterminal or your choice of Terminal Emulator

You may download:

• FORTH - Original version as I received it. Expects an 8251 UART.
• FORTH - Modified to operate on the Space-Time Productions SBC, using Z-80 SIO, and compile using TASM.

Since I am using TASM to compile my ASM files into loadable Intel HEX codes, I had to change most of the parameters from the original into usable devices. (i.e. -

• Replace DW with .WORD
• Replace DB with .BYTE
• Replace ORG with .ORG
• Replace DS with .EQU and calculate the address for the storage item.
• Remove the 8251 UART initialization routine at the start near $8000.
• Replace the 8251 driver routines near the end with SIO routines.
• Replace hexadecimal notation like "#30h" with $30, which was causing errors during assembly.

I noted the routines "S0" and "R0" were referred to in the original sometimes as RO instead of R0 [Zero "0" versus the letter "O"]. I corrected this throughout.

I was sucessfully able to relocate this program to $5000 and other locations, but when I tried to load it to $1000 (for burning to Rom 2 & 3) it blew up. I'm initially guessing it wants to find RAM in the page immediately following the program (which would be $3000, another ROM on my computer). I (sorry, folks) don't have time to troubleshoot this right now, so I'm offering it "As is". It works quite well in upper memory, just load it and Go to $8000 to start.

You may wish to edit the addresses for the mass storage areas and the stacks so that it may take advantage of more of your system's ram configuration. I decided, after some goofing around with this at different .ORG addresses, to return it to its native home at $8000. Some configurations worked, others caused strange effects or "locking up" for no apparent reason.

The program reports errors and problems as "? MSG # 01" or "? MSG # 17" and I have no idea what this means. To tell you the truth, I really don't know much about the FORTH language, but can do some simple calcs and routines on it, thus it appears to be working as the original product advertised. There is a wealth of FORTH programs you can get for free, as well as several on-line tutorials that I was able to easily locate using Yahoo.

In case your Space-Time Productions board is only using the onboard 2K bytes of Ram, you won't be able to get it to work. It simply requires more memory than a standard config'd board can offer.

Added February 23, 2007.