Quote from: KNK on November 06, 2013, 08:27:41 PM

74AVC4T245 is what i am testing the chips with and the reason for adding ActiveLowOE, but you did it the wrong way with two chips i think, because you won't be able to control two banks separately that way ... except if you use the two groups of each chips for two separate banks, but then why not just make them as In/Out on the same chip and the other one for the next bank?

I'm not trying to do banks, my board is a single chip development board, main purpose: learn to use Altium. 2nd purpose: a board to experiment with (hardware and software) so I can make larger more sophisticated boards in the future.

Quote from: KNK on November 06, 2013, 08:27:41 PM

Quote from: cscape on November 06, 2013, 07:16:24 PM

For chaining you just connect 2nd chip to 1st chip without level shifters. The whole chain runs at 1.8V, and you only need to convert to 3.3V between first chip and host.

As cscape said - chaining the chips is by connecting the first chip outputs to the second chip inputs without any level shifters. You need different LS for the different banks only and then you enable each bank by it's own OE

With some crazy wiring (board design) you may even go for 3 banks with only 2 LS if you want to be stingy

cscape is of course 100% right, but hey, I work on these things late at night after the kids are asleep... so level shifters: if one is good, then two must be better. Also, you could make an argument that when driving board-to-board 3.3V has a better noise margin than 1.8V.

Anyways, all moot points as this version of the board will never get fabbed again, and it has met several goals, one of which is proving out the power supply design.

Fun discussion, you guys would be no fun in a design review ;-p

-a[g