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Luis (CocoDemus) has recently shared on the cocolist his design for an 80 column CoCo WordPak cartridge based on the CRT9128 chip.
Here is his demonstration video: http://www.youtube.com/watch?v=HGsoAUJbZi4

I can confirm that his design works great also on the Dragon!

My Dragon now displays nice and sharp 80X24 lowercase letters, both under Basic and NitrOS9. (The photo doesn't do it justice)



I have patched Luis's OS9 drivers to support Dragon Data's GO51 escape codes.
With these patched drivers you can run Dragon Data OS9 applications like Stylograph, Dynacalc and RMS as well as Tandy OS9L1 applications on the 80X24 text screen.



Luis's CoCo Basic driver works on the Dragon without any modification. You can select PAL or NTSC display with a single poke.
The driver is a simple hook to basic that mirrors any text that is printed and typed on the Dragon to the CRT9128 screen.

The WordPak board has it's own 2k display memory, which opens many possibilities for dual screen applications.
For example, run a program on one screen, and monitor/disassemble the code to the second screen. How difficult would it be to patch DREAM to do that?

Luis has shared his project on OSH Park. You can order the blank PCBs directly from https://oshpark.com/shared_projects/iA8mteUe for about $19 a piece.

Here is the component list for this board:

• CRT9128
  6116P
  74LS688
  74LS133
  74LS05
  10.92 MHz Crystal (11 MHz will do just fine)
  2N2222
  0.22 uF Capacitor (224)
  1K resistors (X2)
  5.1K resistor
  750 Ohm resistor
  22 Ohm resistor
  25 Ohm resistor
  RCA socket
  2.54 mm Pin headers (for jumpers)

Most of these are readily available on ebay/electronic suppliers.
The CRT9128 is not listed online, but it is available from several chinese sources. The cheapest I have found is from cathy@shengxinelec.com
Once you have all the parts this project is not too hard to assemble. The board fits nicely in any CoCo rompak case.
The only catch is that OSH park makes you order the PCBs in batches of 3. So guys, get together and order them

You can download the schematics and CoCo drivers from Luis's site here: https://docs.google.com/viewer?a=v&pid= ... GNjOTEyZmM
Attached is my Dragon Drivewire NitrOS9 80 column boot disk with patched Dragon compatible CoWP PAL drivers. Drivewire is not required to use this board, but without drivewire you would need a y-cable to plug in both the WordPak and DragonDOS cartridges.

Ever wished you had a DragonPlus board? Well, the WordPak is just like a DragonPlus just without the additional 64K ramdisk

I would like to port the Compusense Edit+ for DragonPlus to work with the WordPak board. The only versions of Edit+ I was able to locate are for standard HiRes screen. Does anyone have a copy of Edit+ for DragonPlus?

Cool, So I might test my new WordPak2+ on my Tano dragon as well

The NitrOS9 disk image above also includes patched copies of Stylograph and Dynacalc.
Stylograph is patched for 80 columns and additional keymap patches (for more logical key assignments) as featured in Dragon User 3'87. For Dynacalc, I've used the Tandy version since it has optional support for mouse/joystick. I've patched dynacalc.trm to add support for highlighted (inverse) text for column and row labels as used in the Dragon Data Dynacalc release.

Louis has encountered overscan issues with the CRT9128 using some monitors. I'm using a GrandTec GVC1000 composite to VGA adapter (PAL) and did not have any issues. These problems seem to be less of an issue for PAL displays, and if encountered could probably be compensated for by updating the drivers (for 78X24 effective display).

Here is the NitrOS9 80 column wordpak boot disk in DragonDos format, as requested by Pere.
With this disk image you can use the WordPak without drivewire. Of course, a y-cable or a multipak interface is required in this case.

UPDATE: added DragonDos disk image with the Basic WordPak drivers.

I have nothing practical to add to this thread, but I just want to say it's awesomely clever what you've done here. I love the idea of 80 columns and potentially multi-monitors on my Dragon 32. It amazes me that after 30 odd years, exciting new things are *still* being developed for this computer!

tjewell wrote:I have nothing practical to add to this thread, but I just want to say it's awesomely clever what you've done here.

I second that statement. Simply awesome!

-- Rolf

The credit goes to Luis (aka retrocanada76) who designed this board.
Luis's board is based on Tony DiStefano's design which was featured in the June 88 issue of the Rainbow.
Luis has added several improvements like base address selection and shared his improved design on OSHPark.
Here is the original rainbow article.

Thanks so much for sharing this, Luis! Also to KenH for documentation and for helping me getting a PCB I was able to demonstrate this at my Dragon presentation last night. Since it took a while to get the right components I had made a first version without the decoding logic (74688 and 74133) and instead hooked the cartridge port P2 signal to the CRT9128, and also used an 8K SRAM instead (needed some fine wire art to fit this 28-pin IC into the 24-pin socket). This resulted in some characters missing. Just yesterday I received the missing pieces and could do a "live" fixup of my board. We understood that the missing characters in my first version were due to the missing gating of the CS\ signal with the Q clock line...

BTW, can anyone explain why Q is used instead of E? I have sometimes seen E or'ed with Q to get a longer select pulse, but as I understand it the 6809 has valid data on the bus only some time after Q goes high. Of course if the CRT9128 is a bit slow at reacting this works fine.

Luis, there is a small bug in your BASIC driver: A $7E (JMP) is stored at $179 but no address at $17A. This works fine under HDBDOS because there is already a hook installed there in this case, but it crashes on pure BASIC. Removing the "STA $0179" fixes it.

It's a strobe line. And IRRC when Q goes hight E is already high.

You guys must see the V9958 card. It's amazing: Showing up to 19 thousands simultaneous colours on screen and hardware sprites and hardware scrolling

That's the video chip from the later MSX computers? Has someone interfaced this to a Dragon or Coco? Seriously cool if they have! And I guess, given it works with a Z80, then that's not impossible ...

Tony