74HC Datasheet, 74HC stage Binary Counter Datasheet, buy 74HC, 74HC pdf, ic 74HC description/ordering information. The ‘HC devices are stage asynchronous binary counters, with the outputs of all stages available externally. A high. Data sheet acquired from Harris Semiconductor. SCHSD. Features. • Fully Static Operation. • Buffered Inputs. • Common Reset. • Negative.

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Interesting discovery upon looking back In this case, it’s not memory but registers.

About Us Contact Hackaday. Doesn’t look promising – although the typical 21ns 6V or 25ns 4.

Maybe a fast external counter for the lowest 4 or 8 bits, and the PIC generates the upper ones? VHC to the rescue? If I were going to build a bunch of these, I’d try harder to get the 74HC to 74hc404.

74HC Datasheet pdf – stage binary ripple counter – Philips

Synchronous counters use extra logic to form the next state from the previous one directly, without waiting for clocks to ripple through, so the outputs settle faster. This also ignores the fact that two 74HCs need to be chained to generate the bit address: This could be interesting.

Maybe I’m doing this wrong? I think either one would definitely work, and it would make an interesting project, but I’ve somehow got it into my head that I need actual x Cycling back the hsync for a second counter is interesting.



This would work – with the 12ns SRAM access time, still way under the 40ns cycle time. I’m already bummed about the color thing For Qd the fourth bitthe typical tpd is given as 8. Musta been a bunch of pixie-dust in there, or a poor memory of 18 years ago.

Monitors can handle some clock frequency variations.

74HC data sheet datasheet & applicatoin notes – Datasheet Archive

I started with the VHC part this time: I’m using typical values for the moment; if it doesn’t work there, it’s not going to work worst-case, either. That should relax some timing as your MSB are no longer rely on the propagation from the lower bits. Interestingly, it also has a synchronous clear, and connections for synchronous expansion between counters with lookahead carry outputs.

Sign up Already a member? I haven’t used VHC logic before, but keep seeing it around. Surely the 74VHCwith its Mhz typical max clock frequency will do the job! So, what the heck, I’ll look at timing before slapping something together.

I Hate Ripple Counters

I’ll have to give that one some thought. It’s a shame, because the ‘ packs bits into a single package. What about using datashert fastest PIC available and bitbanging the address lines?

The dot clock is Synchronous Counters Synchronous counters use extra logic to form the next state from the previous one directly, without waiting for clocks to ripple through, so the outputs settle faster.


The row address can be updated from the horizontal sync. Even if you could output a new address every cycle, that’s still only about half of the All these numbers involving multiples of propagation-delays are making me question even further how I got the ol’ LCD datashet running. Since it’s a ripple counter, Q0 flips, then Q1, then Q2, etc, so we have to add all the delays so see how long it takes for the address to settle to the datasheey value.

Here’s a simplified schematic of the guts of the VGA framebuffer it ignores the reset and connections between the two ”s required to generate 19 bits of address. Yeah, I had read about keeping video blanked outside of the active area.

Now, I need 5 ICs to make the counter – if it’s even fast enough. The 74VHC is another candidate – it has twin 4-bit counters in a package, so three ICs would be necessary. I’m going to ignore those timing calculations for the moment next log because there’s an even bigger problem here – it takes too long for the address to settle.