Hi,
Attached the docs of a ZX81/TS1000 EPROM I/O programmer port, that I was able to interface to a PC.
I'd be interested in any comments . . .
b
ZX EPROM Programmer Port
ZX EPROM Programmer Port
- Attachments
-
- EPROM-IO.pdf
- (20.09 KiB) Downloaded 246 times
Re: ZX EPROM Programmer Port
Does this device use an 8255 IC?
DesSony
DesSony
Re: ZX EPROM Programmer Port
Another card here based on a 8255 : http://zx81.ordi5.free.fr/brico/ui/5) I/O CONTROL — performs single 8255 I/O operations. The seven
operation mnemonics are: WR PA, WR PB, WR PC,CNTRL, RD PA, RD PB, and
RD PC. For WR and CNTRL operations, data will be requested; for RD
operations, data will be displayed in parenthesis.
("Micro-Systeme" 1984,Nov http://fr.1001mags.com/parution/micro-s ... embre-1983 )
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
Re: ZX EPROM Programmer Port
I have 2 EPROM burners for the 81 . One uses some kind of cobbled together logic chips and the other one is an 8255 device which can burn most of the old 21/25v devices when attached to either the 81 or the spectrum although I only have the spectrum software to run it(the guy who sold me it said it would come with the 81 software but came in fact with the speccy software!)
I use it to burn what ever new 81 ROM comes to the forum and have no need for PC burners which seem to struggle with the 21/25v end of things, I guess I'm a bit old fashioned when it comes to things like this.
I use it to burn what ever new 81 ROM comes to the forum and have no need for PC burners which seem to struggle with the 21/25v end of things, I guess I'm a bit old fashioned when it comes to things like this.
- 1024MAK
- Posts: 5120
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: ZX EPROM Programmer Port
That’s because some of the cheap PC EPROM burners were originally designed to burn chips for automotive use and not old computers...
The problem with them is in the design and construction quality of the DC-DC converter. Where an external power input port is available, and they can take an external 12V DC input, they may then manage to program 21/25V EPROMS.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: ZX EPROM Programmer Port
Excellent explanation as always Mark, many thanks for that.1024MAK wrote: ↑Sat Jul 06, 2019 12:49 amThat’s because some of the cheap PC EPROM burners were originally designed to burn chips for automotive use and not old computers...
The problem with them is in the design and construction quality of the DC-DC converter. Where an external power input port is available, and they can take an external 12V DC input, they may then manage to program 21/25V EPROMS.
Mark