DFB1r4 design discussion thread

[Steve]

Amazing work @Badwolf So glad you're making progress!

[Badwolf]

Amazing work @Badwolf So glad you're making progress!

Thanks, Steve!

Unfortunately I just discovered another design boo-boo which torpedoes this batch of boards, though.

I was scratching my head as to why the full 64MB could pass the memory tests with YAARTTT, but then everything would go to custard when I tried to add AltRAM: I've inadvertently put a byte 3 line to the byte 4 port of one of the memory chips (and vice versa)!

Basically with D23 and D31 swapped, word and longword writes will succeed fine but byte writes to either byte 3 or byte 4 of the port will fail as it will be latching one line from the other byte instead. YAARTT only ever performs word writes, so this wasn't a problem.

Bah!

I hope I can cut these two traces and patchwire this board for continued dev, but with three patch wires on the board already, I think it's going to need a respin before I get a release version.

Damn and blast.

BW

[exxos]

I feel your pain there!

We need a group hug smiley. But I guess this one will just have to do..

[JezC]

I feel your pain there!

We need a group hug smiley. But I guess this one will just have to do..

I thought you'd added this one for these situations?

[Badwolf]

We need a group hug smiley. But I guess this one will just have to do..

I thought you'd added this one for these situations?

It's interesting how Chris' mind goes straight to the chair whack, ain't it?

BW

PS: here's the oopsie.

Screenshot 2021-09-24 at 15.28.30.png (209.33 KiB) Viewed 1697 times

[JezC]

It's interesting how Chris' mind goes straight to the chair whack, ain't it?

BW

Also, if you read TF's reply to my post on his general letter topic, that puts it in a totally different light!

[Badwolf]

Also, if you read TF's reply to my post on his general letter topic, that puts it in a totally different light!

[JezC]

Also, if you read TF's reply to my post on his general letter topic, that puts it in a totally different light!

And then the latest response to that from @exxos

General question: does invalidate the smilie?

[exxos]

General question: does invalidate the smilie?

Nope.. You get hit over the head with the chair your under..

[Badwolf]

OK, my shonky design confirmed.

IMG_4747 2.jpeg (216.68 KiB) Viewed 1661 times

IMG_4749.jpeg (135.89 KiB) Viewed 1661 times

IMG_4748.jpeg (118.25 KiB) Viewed 1661 times

(All these at 16MHz)

Now, how fast can we get this to go..?

BW