dhe

Brings to mind, TI's three failures.. Wafer Tape (String Drive), GROM Library Boards and IR Remotes.

This VVV saddens me, I think we all remember the 90s when occasionally something would be bid high - because two or so determined bidders went at it. Now, I see LOTS of profit taking in retro auctions, even auctions that start at impossible numbers, hoping someone will bite. Sad Times.

Depending on how much space is left in the DSR EPROM it might be possible to add DSK capabilities, but certainly not a minor project. @jedimatt42 has shown all of us, the awesomeness of having everything available in a public github.

@Shift838 I have two cards for the TI (SCSI and RS232) - that don't have the screw in post for the 25 pin connector. I hope you can source 25 pin connectors with screw in mounts for the cable.

@visrealm I thought I wasn't paying attention. Looking at the first photo of the board it looks like the ribbon cable is on the top (like TI's), then looking at other photos of the board on github, the connector seems to be in the middle of the board. Did you recycle a ribbon cable from the original keyboard? I really like how you labeled the pins - that's a big help for us hobbyist. Thank you for creating this, good working keyboards for the ti-99 are getting scarce.

This is kewl. SCSI always represented the premium solution. More devices, and a more feature rich controller. BITD - always appreciated the Adaptec controller menu popping up on a PC and being able to see what type of device, format and verify all from ROM and in addition RAID, vs MFM, RLL, IDE - hook as master or slave unit and set jumper, enter in bad sectors. I'll be buying one also!

Finally had some time to go back and play with a small bit of assembly. I've been proof reading an english translation of the german assembly books kursi. One of the comments he made in an example was that, we needed to get the MSB in to the LSB position for the next instruction. He mentioned instead of using SWPB, we would use SRL, while that does move the MSB>LSB, you loose the value of the LSB (unless it's already zero! 😃 ). Using Steve's Cheat Sheet, I was able to quickly grab the instructions FMT, using xdt99's listing, I quickly got the number of clock cycles. - using a shift instruction cost double the clock cycles as swpb, tested by single stepping with Classic99. That got me thinking about another example I've seen, which is setting a register to zero, by using XOR. That also costs four additional clock cycles over LI or two additional clock cycles compared to CLR. With CLR being the easy winner for expressing intent.

Thanks @airernie - I'd have bet dollars to doughnuts, that had already been put on whtech.

Maybe my search FU isn't up to snuff. Does anyone know if there is a copy of John Willforth's ProtoTyping Manual on whtech - or can someone please upload a copy here?

Kewl.. But get out your checkbook! https://www.ebay.com/itm/235501953488

Where is said guide?

I was re-re-reading the VDP Programmers guide. I noted three additional manuals were listed. I found one, attached. I also noted they mentioned the Advanced VDP. I found a patent application from 1992 - attached. SPPA004A_9928-29_9118-28_Interface_to_Monitors.pdf US5089811.pdf

I love it when I make a connection. Always known we have VSBW and VMBW, I just kind of went with the flow on that, but then I saw this little snippet in the VDP Programmers Guide: "The VDP is connected to VRAM via a 14-bit auto-incrementing Address Register. Once the address to read from or write to is set up (two-byte data transfer), we can read or write a byte of data using a one-byte transfer. Continuing to read or write to the VDP causes the address to increment automatically. Therefore, reading or writing a sequential chunk of data can be performed very quickly." Hence, why two utilities instead of one. I also double checked, yep, with 14bits, you aren't getting more that 16K...

Would you mind giving a mini tutorial on how it works or is that documented else where?

To much? 🤔