MaxIO project.(INPUT) [KICAD; ZX81/SPECTRUM]

[XavSnap]

Done !

Back_connector_Ext_ZX81_Gerber.zip

(18.31 KiB) Downloaded 147 times

[EDIT] : Previous messages updated with the Gerber files. (only the rear connector PCB used in this project)

Have fun !

OUTPUT MaxIO project :
https://www.sinclairzxworld.com/viewtop ... f=7&t=5728

[jeffounet]

This is great, thank you.

Jean-François

[jeffounet]

Hello Xavier,
I just received the PCBs of the MaxIO series (inputs)
And there is on the monitor card a circuit that I can't find U2 which seems to be a hexa/binary converter.
Do you have the exact reference of the component as well as the place where we can supply it?
Thanks in advance
Jean-François

[XavSnap]

Hi Jean-François,

The 'HEX7' was a preprogrammed circuit using a GAL, the GAL22v10.

https://www.alldatasheet.com/datasheet- ... 2V10D.html

[EDIT:
The VCC and the GND location are wrong on this ship, i can't retrieve the right GAL name !
The GAL22V10 have only 24 pins. (can be host on an another PCB)
We have to drive 8inputs and 14outputs... + the sync/cs.
Note: All segment are active if the output is low ! (POL=GND)
Led on=/Q=0
]

The demo program is include in the GAL burner software.

Just use the clock signal as an input...
Have a look to the pin assignement (INPUT/OUTPUT) to rebuid the shipset.

https://www.quora.com/Can-we-show-hexa- ... nt-display

[XavSnap]

Hi Jean-François,

There is a CENTRONICS GAL22v10 (PLCC version) programmer in the "INTERFACES PC" #6, but it's in french...
Here:
https://www.abandonware-magazines.org/a ... &album=oui

The ZX81 release from the Patrick Gueulle project:

ZX81_GAL22v10_Prog.pdf

(163.29 KiB) Downloaded 114 times

[XavSnap]

Hi Jean-François,

Exit the GAL22v10 component.
To replace the HEX7 chipset, i finally use a double GAL16v8 synchronized system.

Have a look the this web page to get the source code; https://www.instructables.com/Dual-BCD- ... nt-Driver/

My replacement addon is available here, two GAL16v8 on a PCB to insert in the "HEX7" 28 pin slot:
Gerber/Kicad PCB project
https://forum.abandonware.org/viewtopic ... 443#p40443

[jeffounet]

Thank you for everything!
Have a nice day

Jean-François

[XavSnap]

Hi Jean-François,

A new PCB from "Electronique-Pratique" #288 : GAL16v8 & GAL22v10 programmer on printer port (CENTRONICS)

Is available here: http://abandon.pcbs.free.fr/ElecPratique.htm

Have Fun.

[jeffounet]

Good evening everyone,
@XavSnap, thank you for this new project.

Jean-François