Search found 4371 matches

by exxos
Tue Dec 11, 2018 10:43 pm
Forum: MONGREL EDITION (version 2)
Topic: RGB DAC ADDED
Replies: 0
Views: 24

RGB DAC ADDED

Before...
vd.JPG
vd.JPG (65.02 KiB) Viewed 24 times

After...


sh1.JPG
sh1.JPG (87.07 KiB) Viewed 24 times

I guess something to ponder next is if to add a multiplexer to switch MONO to the RGB buffers...
by exxos
Tue Dec 11, 2018 10:19 pm
Forum: MONGREL EDITION (version 2)
Topic: RESET CIRCUIT
Replies: 0
Views: 19

RESET CIRCUIT

Before..
22.jpg
22.jpg (9.68 KiB) Viewed 19 times

After :)

11.jpg
11.jpg (18.43 KiB) Viewed 19 times

Pondering that the /MR should have a pull up on there as well...

EDIT:

pdf says 63K internal pull up.. I guess it be ok like that, better than these 1meg+ rubbish some chips have!
by exxos
Tue Dec 11, 2018 10:13 pm
Forum: ALPHA USER BUILDS
Topic: Forgottenmyname - Progress - Part 2
Replies: 17
Views: 153

Re: Forgottenmyname - Progress - Part 2

Hopefully things go well :thumbup:
by exxos
Tue Dec 11, 2018 9:48 pm
Forum: MONGREL EDITION (version 2)
Topic: POWER CONNECTORS
Replies: 3
Views: 37

POWER CONNECTORS

What format do people want these ? There is the PSU connector pinout, or the floppy header pinout... Assume just more floppy power pinouts is what people want ?

pw.JPG
pw.JPG (61.26 KiB) Viewed 37 times
by exxos
Tue Dec 11, 2018 9:29 pm
Forum: MONGREL EDITION (version 2)
Topic: ROM LS11 CHANGED REV H1
Replies: 1
Views: 18

ROM LS11 CHANGED REV H1

I have removed the DIP LS11. The only need one gate here, so I change this for a single gate chip. It is a small SMT single gate one. It will save some space at least.

Also don't panic, I'm not going to start changing the other DIP's for SMT just yet :)




rom.JPG
rom.JPG (54.29 KiB) Viewed 18 times
by exxos
Tue Dec 11, 2018 9:12 pm
Forum: MONGREL EDITION (version 2)
Topic: INVERTER REMOVAL REV H1
Replies: 0
Views: 19

INVERTER REMOVAL REV H1

Image doesn't need high res here, just to show that the inverters at the bottom of the image are ones which have now been removed. Which saves a chip! A second inverter chip was mostly used in the reset circuit, this is now a normal open collector buffer. This saved some gates also. But I needed cou...
by exxos
Tue Dec 11, 2018 8:42 pm
Forum: ALPHA USER BUILDS
Topic: Forgottenmyname - Progress - Part 2
Replies: 17
Views: 153

Re: Forgottenmyname - Progress - Part 2

Doing some more soldering tonight, won't be too far off ready to fire up the board by the end of tonights efforts. :bravo: I'm fitting the DAC shifter board to this STF but can't remember how much of the RGB circuit I no longer need as I'm not soldering if I don't need to :-) You don't need any of ...
by exxos
Tue Dec 11, 2018 5:41 pm
Forum: STF REMAKE PROJECT
Topic: DMA port "update" ideas..
Replies: 117
Views: 2354

Re: DMA port "update" ideas..

Icky wrote:
Thu Nov 08, 2018 10:27 pm
I don't want to go through that NASTY DMA / BAD 1772 debacle again.
Now the 1772 board is in place, it *might* be worth pushing 16MHz into the DMA again and see what happens...
by exxos
Tue Dec 11, 2018 5:00 pm
Forum: MONGREL EDITION (version 2)
Topic: REV H DMA / 1772 mods
Replies: 1
Views: 29

Re: REV H DMA / 1772 mods

I've added in the DMA port buffer... Also updated the DMA connector pin labels... 2.JPG A few other things on the STE were buffered... Capture.JPG I guess it would help if someone with ultrasatan could measure the DMA port signals which are shown to be going via the LS244 buffer to see if they need ...
by exxos
Tue Dec 11, 2018 4:46 pm
Forum: MONGREL EDITION (version 2)
Topic: REV H DMA / 1772 mods
Replies: 1
Views: 29

REV H DMA / 1772 mods

I started a new schematic , so we on REV H now. I've added in the 1772 buffers... Though I actually realise we should probably have pullups both sides of the buffer... When the 1772 bus was linked to the DMA, it only needed one pull up array.. I can't remember what we decided to add now, but think w...