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Re: exxos blog - random goings on

Posted: Mon Nov 04, 2019 7:42 pm
by PaulJ
exxos wrote:
Mon Nov 04, 2019 7:18 pm
Yeah , took some doing, JLC wouldn't even make the board because of its specs :roll:

I've done multiple alt-ram boards over the years, none produced. But this is just the bare SRAM board, it pretty much will never change. But it can be made to work with anything which has a PLD, like flashyclock, and the SEC booster etc. On this arrangement the PLD logic to drive the alt-ram board is "free".
Pretty neat design, looks like the larger part of the pin goes through board. How large will the ram size be?

Re: exxos blog - random goings on

Posted: Mon Nov 04, 2019 7:48 pm
by exxos
PaulJ wrote:
Mon Nov 04, 2019 7:42 pm
Pretty neat design, looks like the larger part of the pin goes through board. How large will the ram size be?
8MB. 4 IC's 2MB each.

Re: exxos blog - random goings on

Posted: Tue Nov 05, 2019 12:23 am
by Icky
exxos wrote:
Mon Nov 04, 2019 6:03 pm
PhilC wrote:
Mon Nov 04, 2019 6:02 pm
AH, now I remember.

Hurry up then Icky :lol:
Icky is waiting on me to do the firmware for the current boards :) I kinda been busy lately :)
Busy - I would call it yak shaving some routing ;)

Re: exxos blog - random goings on

Posted: Tue Nov 05, 2019 3:30 am
by rpineau
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Re: exxos blog - random goings on

Posted: Thu Nov 07, 2019 11:54 am
by exxos
Very close...

Need to order some SRAM chips, can only find 10 :roll: Then will send off for 10 prototypes to be made. Need to get back to flashy-clock ASAP :roll:

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Re: exxos blog - random goings on

Posted: Thu Nov 07, 2019 6:34 pm
by exxos
New book :)
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Re: exxos blog - random goings on

Posted: Fri Nov 08, 2019 4:16 pm
by exxos
Busy scrapping machines today, mostly STFMs. Finally found a original TOS104 2 chips set which is in my store now.

ST chips such as, DMA,GLUE,MMU,SHIFTER, TOS (104) are appearing in my store. Price is high as the only source for chips is old machines, which are generally costing £60+ these days and there's not a huge amount I can strip off to recover the costs. Other chips are not really taking off as I am buying them in new anyway.

I will be taking off some DB19's and cartridge connectors from scrap boards for my store at some point also. I'm probably not bothering in taking the RAM or PLCC sockets off, but if someones wants to offer £10 a board, then may be useful for some spares. I could take the sockets off and sell in my store, but really don't have the time, and have no objections if someone else whats to do that. I am getting a bit swamped with scrap boards so need to do something with them.

Re: exxos blog - random goings on

Posted: Fri Nov 08, 2019 8:20 pm
by exxos
I had finished my cheap VGA adapter, but lost the PCB's :roll: Though I decided I didn't like how dark the thing was. It was useable with monitor turned up full brightness, but I really wasn't happy with it like that. I was trying to use a 12V multiplexer to avoid using a regulator like UBE does. Though all the 12V chips had over 120R series resistance which is why the brightness was so dim. So I went for the same chip the UBE uses, but instead of a regulator, I am clamping the 12V to 5V with a zener. The 12V to the monitor port goes via 1K or higher resistance so the current is only 5mA ~ 0.025watts.

So now the new version 4 test boards are being made..

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Re: exxos blog - random goings on

Posted: Mon Nov 11, 2019 2:26 pm
by exxos
Trying to bring order to chaos.. Don't think I am winning...


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Re: exxos blog - random goings on

Posted: Mon Nov 11, 2019 2:57 pm
by PhilC
And I thought my desk was messy