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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I spent the afternoon re-working my ugly SOIC adapter board designs to reduce the ground-connection impedance and add on-board bypass caps.

74hc44040 have to give that one some thought. Cycling back the hsync for a second counter is interesting. I’m using typical values for the moment; if it doesn’t work there, it’s not going to work worst-case, either.

So, what the heck, I’ll look at timing before slapping something together. In the store-each-dot-period-as-a-byte plan, this is trivial 74hc404 I have full and easy control of all the singals on on a per-dot basis. Add in the 12 ns access time of the SRAM, and we’re definitely over budget. Did I miss something on the ripple counters? In the schematic above, the ‘ counters increment the 74hc40400 on the rising edge of the clock, while the ‘ d-flop captures the data from the last address before it changes.

This also ignores the fact that two 74HCs need to be chained to generate the bit address: If I were making more than a one-off project, I think the 25 MHz idea might be the way to go. In this case, it’s not memory but registers. Interesting discovery upon looking back The row address can be updated from the 744hc4040 sync.


For Qd the fourth bitthe typical tpd is given as 8. About Us Contact Hackaday. Surely the 74VHCwith its Mhz typical max clock frequency will do the job! 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 Now, I need 5 ICs to make the counter – if it’s even fast 74hc400.

Maybe I’m doing this wrong?

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 next value. This could be interesting. The dot clock is I have a tube of 50 MHz cans around here that I could divide down, but since I have to order parts for this thing anyway, I might as well pick up the exact frequency for a few bucks. 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.

They’re not completely general anymore, since now they assume standard corner pin supply connections, but they should be better for signal integrity.

74HC datasheet, 74HC datasheets, manuals for 74HC electornic semiconductor part

Next step – the rest of the logic and timing calculations. Yeah, I had read about keeping video blanked outside of the active area. I started with the VHC part this time: I can hook one to the four-channel scope and have a look at the delays between the LSB and successive bits. I’m already bummed about the color thing This would work – with the 12ns SRAM access time, still way under the 40ns cycle time. Sign up Already a member?


74HC4040 Datasheet

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. What about using the fastest PIC available and bitbanging the address lines? Interestingly, it also has a synchronous clear, and connections for synchronous expansion between counters with lookahead carry outputs. I saw the 25 MHz trick in your terminal project – good to know. The clock input on the ‘ works on the positive edge, so the schematic above changes a bit, but at least the addresses seem OK.

Yes, delete it Cancel. All these numbers involving multiples of propagation-delays are making me question even further how I got the ol’ LCD controller running.

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. Synchronization is an issue, but it’s worth thinking about – maybe if the PIC runs from the external It’s a shame, because the ‘ packs bits into a single package.

That should relax some timing as your MSB are no longer rely on the propagation from the lower bits. Doesn’t look promising – although the typical 21ns 6V or 25ns 4. If I’m reading the datasheet correctly, the maximum delay from clock edge to valid outputs is If I were going to build a bunch of these, I’d try harder to daatasheet the 74HC to work.