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Not much: a couple of 6845 registers need to be set up, just like a MDA card (in fact exactly like an MDA card) and you can trigger some extra functions through specific IO ports to enable the graphic functions and RAM pages. After setup the card shows up as 4 k of video ram space with a 80x25...

I recently hooked up a Tamarack 8 bit ISA Hercules Graphic Card to my Microprofessor 1 Plus just for fun. Used a GAL 16V8 to generate the necessary ISA bus signals and a LS123 to delay and drive the /WAIT line of the Z80. Works quite nice but ofcourse it does not generate VGA, I use a Qtek MDA...

Well, there was ofcourse CP/M86 ... ;)

Tried it on Z80 BBC basic on my 'Kaypro mini'

Since you can use recursion on the BBC it is designed so local variables are 'fresh' for every call to the function. Just try it out: REPEAT INPUT "Enter an INTEGER less than 35 "num UNTIL INT(num)=num AND num<35 fact=FN_fact_num(num) PRINT num,fact END : DEF FN_fact_num(n) IF n=1 OR n=0...

Another common fault where multiple chips are fried: a bad power supply. Always check voltages from the supply before connecting it.

Might take a look at x11basic: https://x11-basic.sourceforge.net/

Have a look at: http://q7.neurotica.com/Oldtech/Kaypro/Kaypro488.html There are some photo's of the innards of the Kaypro 4 plus 88 including the 8088 board (alas a bit obscured by the cables) but might give some insight how it wa attached to the Z80 board.

A little Google-ing and translating from this website: The system also included a typewriter (it appears to be from the ET series) equipped with a serial interface LCU ( Line Control Unit ) so as to use the keyboard section as input and the printer section as output. The connection between...

Mangled a pin of the 6845/6545 perhaps?

Thinking of it, the Amstrad PCW (or Schneider Joyce) may be an excellent candidate for MPM as it has 256 to 512 kByte of memory available in 16 kByte chunks which also can be mapped in 16 kByte offsets: &F0 O Select bank for &0000 &F1 O Select bank for &4000 &F2 O Select bank for...

I had a NEC P6 24 pin printer connected to my Atari ST and with the Signum3 DTP-ish software package I printed a lot of invitations, letters, school work, wedding cards and such. It printed absolutely beautiful (for those days) and quality was almost on par with a 300 dpi laser printer.

Note the Teensy has 3.3V IO so you need the MAX3232 instead of the MAX232, otherwise you need to level convert the input to the Teensy first. Can be done with some resistors but maybe you run into speed problems then.

As far as I can tell the only 'forum' Agon Light is using is FB and since I am not using FB... I am fiddling here with a sort of 'Agon Ultralight': VGA32 (with ESP32) miniboard which handles all the work: emulating a Z80 (I could do 6502) and generating VGA signal, sound, SD card storage etc...

Good work!

My first Atari was a 400 (a leftover in the shop I worked), got a 1050 diskdrive with it and expanded the memory myseff. Can't remember where it went. Later on I got a 260ST, updated it to 1 Meg and a SH204 harddisk, the drive in that got replaced by a 'real' SCSI 2 GB drive, after that a Mega...

You can send an Intel hex file over serial as text, save it on the CPM side (you can use PIP for that too!) and use DDT to read it into memory. After that you can use 'SAVE' to save it as a binary to disk. Crude but effective.

It seems like a contradiction if the base drive of Q105 is ok and there is no collector current (note: through T101 the base is mostly current driven since 'high voltage' transistors of that era have very low hfe or gain values). If the collector is at 'solid +12V' it could mean: a) the...

The keyboard matrix with the C64/128 is shared with the joystick ports. So my guess is that the RetroRadionics Arcader is loading some pins of the joystick port and thereby interfering with the keyboard. Try for example holding a standard joystick in port 2 to one direction and then typing...

I assume you are kidding here or do you have any evidence for that ?