Cool that this should turn up just when I'm working on a design that needs one AND but has an unused OR.

The consensus appears to be that propagation delay would kill the whole enterprise unless you knew what you were doing. Well, that wouldn't be me. :oops:
Let's reason it out: The 1N4148 test ...

Double thanks, Jeff. I remembered that extreme stacking thread and wanted to see if anyone else had tried stacking chips of different widths, but couldn't find it.

I wanted to see if a skinny dip, such as a 20nS SRAM, could be piggy-backed to a wider (and possibly slower) device, such as a 70nS EEPROM.

The differences in length and # of pins of the two sacrificial ICs were unimportant for this exercise: What matters is the different widths.

I unbent the top ...

Reassuring responses, some verifying things I suspected, but wasn't sure of. Thanks.

(For that mater I have often just tied the /CE directly to ground for some circuits where I don't really need it.)
I've wondered about that, and how it relates to most devices' datasheets stating Write can be /WE ...

Has anyone experienced or heard of problems when accessing fast memory slowly? Such as 20-55nS sram being accessed with 500nS /CE?

Google and Bing Searches have only given me page after page of Stack -vs- Heap, registers -vs- files -vs- arrays - vs- database queries -vs- etc. Maybe I haven't asked ...

The NOR and inverter generate what the schematic call SØ1 and SØ2. SØ1 enables BLocK0 (the lowest 8K segment of memory) shared with 6560 Vid Controller during the video phase, and SØ2 enables any resource -- including BLK0 -- during the cpu phase. NORing Ø1 out with Ø0 in and inverting the result ...

Yeah, 2MHz would be a decent speed up, but considering the advice in this thread http://forum.6502.org/viewtopic.php?f=4&t=8336 regarding minimum propagation delays I've concluded 4MHz might be doable. (Actually four ticks of 14MHz/2=7MHz.) But whether 2MHz (Two ticks of 3.5MHz), or a portion of ...

Hollerith and Jacquard high five while off to the side Babbage sulks.

Has anyone else seen CPLD's fail in this way?
Retention life deteriorates with each programming cycle, which is typical of these devices. In theory, the claimed data retention life of a device is usually unchanged as long as you don’t exceed the maximum allowed number of programming cycles. Your ...

Thanks all.

My concerns are definitely about a hobby project. Ive been going by the Typical prop values given, and for chips where that value isn't given I've been guesstimating delay would be something between Min and Max, and wondering if I've been being overly cautious. System will run at less ...

How can we make a reasonable estimation of what the actual propagation delay could be between two devices when one or both data sheets for those devices omit one or more of those specs?

Data sheets for the 74xxxx family define prop delay as under a load of C and R. A typical value stated for C sub ...

With different R&C values 555 + 74_06 are the reset circuit for VIC20, C64 and C128. The 74_06 open collector can be shorted to Gnd for a manual reset, but for my VIC and C64 I put a push button to Gnd at the tr pin to get consistent duration reset regardless of how long the button is pressed.

We ...

I'm not much of an expert on the subject, but the numbers you're providing remind me of a subset of what was offered by the MOS 6560 ... perhaps some insights can be gained by studying that chip in more detail?

Datasheet: http://www.zimmers.net/anonftp/pub/cbm/documents/chipdata/6560.zip ...

It's also quite easy to download the image then remove the color by means of photo editing software.

GIMP, Photoshop and Paint Shop Pro come to mind, but even a comparatively rudimentary package should suffice. The menu selections will surely include several pertaining to color, and it's only ...

Cool, cool. Thanks for sharing. Much more versatile than what I came up with in 1989. My utility would save an 80 column screen and its screen editor values to the unused 4K of 16K VDC memory. That's what I had at the time and didn't want to go out on a limb and write code I could not confirm would ...