74LS257 DATASHEET PDF

74LS datasheet, 74LS pdf, 74LS data sheet, datasheet, data sheet, pdf, Fairchild Semiconductor, 3-STATE Quad 2-Data Selectors/Multiplexers. These Schottky-clamped high-performance multiplexers feature 3-STATE outputs that can interface directly with data lines of bus-organized systems. With all but. 74LS datasheet, 74LS circuit, 74LS data sheet: FAIRCHILD – 3- STATE Quad 2-Data Selectors/Multiplexers,alldatasheet, datasheet, Datasheet.

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Hitachi Semiconductor 74LS Datasheet.

If this fails, we need to come up with a plausible theory why, what will take some time. That allows plenty of time, in fact, and this circuit requires only a single gate delay between address logic and RDY, which is about as 74lls257 as you can get. Finally, a low value series resistor 20 or 30 ohms?

This is most visible during the second write pulse. Unfortunately, it is also VERY sensitive to voltage changes, and that’s been a problem.

This 3-STATE output feature means that n-bit paralleled data selectors with up to sources can be implemented for data buses. Mon Aug 06, 1: The first line of defence was to improve cabling.

I may try other values datasgeet to see, dayasheet it’s a guessing game at best. Devices also available in Tape and Reel. Sun Aug 05, 3: These Schottky-clamped high-performance multiplexers.

IC Datasheet: 74LS : Free Download, Borrow, and Streaming : Internet Archive

Just to sum up a few things: I tested the circuit with the 65C02 on a breadboard and it worked perfectly. Major milestone, major success – congratulations Drass!

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You’d definitely want that capacitor across there to prevent that slowing. The problem was entirely the result of a silly error. If this works, we need to come up with a plausible datashee why, what will take some time. I say nearly because I see slight differences between them, several fatasheet which are 10ns variations, and may simply be artifacts of the sampling rate Mhz. Anytime the VFO power supply is substantially higher than the SBC power supply which could happen during powerup or powerdown you can encounter unexpected current flow.

74LS257 Datasheet

I do see the address lines reacting more quickly after AEC changes state. Now here is one of the original objectives of the project as outlined back in The game is called Neoclypssort of a homage to Defender on the C It was a bug, and one that 74s257 gone unnoticed to this point.

This socket goes unused 7l4s257 the TTL CPU is installed, and it conveniently has all the signals we need for wait-stating. Otherwise you could consider other strategies. Features s 3-STATE versions LS and LS with same pinouts s Schottky-clamped for significant improvement in A-C performance s Provides bus interface from multiple sources in high-performance systems s Average propagation delay from data input 12 ns s Typical power dissipation: Previous topic Next topic.

Sun Aug 05, 2: Mon Dec 31, 3: Not sure how one goes about mixing two power sources like this. The simplest fix was to build an small wait-state adapter board to fit the empty 65C02 socket of the SBC. Congratulations to your success!!

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Darn, this one is proving to be very stubborn! This assumes the processor setup time is met.

From the datasheet, 82S propagation delay input to output is 35ns typ. To minimize the pos- sibility dztasheet two outputs will attempt to take a common bus to opposite logic levels, the output enable circuitry is designed such that the output disable times are shorter than the output enable times.

Select a forum That leaves precious little time for address decoding before the rise of PHI2, and any additional delay for clock-stretching or RDY logic will datasehet exceed the time available. Fri Feb 16, 8: Let’s say the load were 30pF.

That helped narrow the voltage gap, so I felt the CPU was more easily able draw the additional power it requires at high clock-rates. Provides bus interface from multiple sources in. Thanks for all the comments Dieter! I used the wait-state circuit we discussed earlier in this thread to insert one or two wait-states when A15 goes high, as follows: