Update1: Buy some flip-pins! See below, they're perty-slick.
Update2: Removing '543, note added...
Update3: Polyimide "Labels" added at the bottom.
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As has been the plan all-along, I'm trying to keep the necessary-parts down to stuff most digital-logic-users either have in their collections, or should...
Here I'm branching out a tiny bit... in the interest of speed and functionality. The odds of your having *the fastest* 74xx245 in your collection are pretty low. But, of course, this system is *now* running at 30MHz on a solderless-breadboard with some HC (and an AHC) parts, and there's no reason you couldn't try to push the limits of whatever 74-series parts you happen to have around.
So far the order contains:
- Si5351A-B-GT
- This is an I2C-programmable "Any-Frequency" Clock-Generator. Attach a 25MHz crystal, and get almost anything from 500kHz to 200MHz on a few outputs. Apparently hacker-friendly, it's even available at Adafruit. With documentation, tutorials, a breakout-board, and an arduino-library to top it all off. (Thanks @Cameron Meredith for informing me of this one!)
- Seriously, this guy could be handy for a *ton* of things, so if it's as easy to work with as it seems, I'm considering it a *belongs-in-toolbox*.
- For sdramThingZero, I intend to use it to generate the sample-clock, which can then be almost any sample-rate between 500KS/s and 133MS/s. BUT: I will continue the design of sdramThingZero with the idea in mind that this is an add-on, rather than a requirement... And you can still supply your own regular ol' Crystal Oscillator as your clock-source, if you don't have one of these in your supplies. (Also, it requires I2C... which isn't as-yet in the plans for sdramThingZero's bus-interface... We'll see where that goes).
- 7400-series chips --I went through quite a bit of data-sheet digging to figure out what to order. I settled on the 74LVT, 74LVTH, and 74ALVC series. I used to be partial to the 74AHC series, but that's a bit slower... Few if Any of the 7400-series faster than 80MHz are available in DIP... And even SOIC is hard to find. I leaned toward SOIC if it was available, but [T]SSOP seems to be more common. I just bought a bunch of breakout boards from MPJA.
- LVT: Really fast, and 5V-Tolerant
- LVTH: Same, but also has "Bus-Hold" (never used that before, but might be handy)
- ALVC: Even faster, but only 3.6V-Tolerant
- 74LVT574, 74LVTH574
- The '574 is the same as the '374, but with a "straight-through" pinout. This is an 8-bit Rising-Edge-Triggered D-Latch. Quite handy to have in your collection. Build an 8-bit shift-register, Latch an 8-bit bus, Create "One-Shot" circuits like those used in sdramThingZero, etc.
- 74LVT245, 74LVTH245
- The '245 is an 8-bit bidirectional buffer, with output-enables. Definitely an important go-to in digital-logic. There's also the '244 (which is really all I need right now), but this is basically the same, but bidirectional, which makes it more versatile for other projects.
- 74ALVC00
- Quad Two-Input NAND. Every logical gate can be created with a combination of NANDs, so invest in these and you don't have to invest in ANDs, and ORs, and NORs, and Inverters, and XORs, or even latches, for that matter. Note that these non-bus-related chips don't seem to be available in LVT[H], so this and the '74 (below) are only 3.6V-Tolerant... Should be OK, since I'm using 'em for internal glue-logic.
- 74ALVC74
- The '74 is a dual pretty-sophisticated-latch. Yeah, I already ordered '574 latches... I debated whether to add these to the list but they're so darned-functional it's handy to have around. Mainly: they have Set/Reset inputs, and also have a normal output as well as an inverted output. I found that reduced *quite a bit* of logic in #sdramThing4.5 "Logic Analyzer"'s one-shot circuitry. I think I'll try to avoid using these in sdramThingZero, but won't try too hard.
- 74LVTH543
- I wouldn't recommend investing too heavily in this guy... and will try to avoid using it in sdramThingZero. This is a bidirectional latch, similar to two '574s back-to-back, this guy is to the '574 as the '245 is to the '244. EXCEPT, that it seems to be hard to find in most 74-families, and I'd never heard of it (in 20+ years of working with 7400's). It's apparently not a "go-to". But it does appear to be quite useful for bus-interfacing. Here's the deal... It's *much* more common in various series as the 50+ pin 16-bit-wide TSSOP '16543. Whelp, I don't have any 50+pin TSSOP breakouts, SO THERE.
- UPDATE: I'mma remove this from my order... I'll keep the '16543 in mind for future-endeavors, but this LVTH543 is over a dollar for a single chip, and I'm broke. Aside from that, it's rare-enough that it's probably not in most hacker-part-bins, so I don't want to design sdramThingZero around it.
I also ordered a couple ATMEGA8515's, again... I didn't really want to invest in such a "lowly" AVR, with so many more-functional ones out there these days... but I've a few projects using these, and as I recall I've only one that hasn't at least one fried GPIO. Those guys are great for prototyping (using one for sdramThingZero, as we speak), but probably good to have a couple *decent* ones around... And, they're only $2.88, whereas the pin-compatible '162 was over double that, and the '644-'2564s are nearly triple. I'm broke. Two for the cost of 2/3rds of one.
So, that's the order, so far... any suggestions as to other similar parts I haven't considered?
DIMM Sockets! Woot, they're cheap, too! But only 451 left in stock after my order, so I ain't linking 'em for yah ;p
This is kinda a boring order... I feel the need for something fun, blinky, or moving...
Update: The pins used in Philip's project #OSHChip V1.0 are now available for purchase for our own projects! This might be just the "fun" thing I need in this order-cycle.
Certainly more fun than damaging my solderless-bread-boards with regular ol' square header-pins. And, can be inserted into a DIP socket, when I've soldered up a board.
I've invested in some for my breakout-boards, and projects down the line.
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Polyimide/Kapton-Tape...
This sh*t ain't cheap.
I managed to come across some "labels" which are allegedly used for barcodes, etc. on PCBs. Not ideal, but cheaper than a roll of kapton-tape. $3.21 for 25 1in x 1/4in labels. This'll be an interesting approach, they're supposedly thermal-printed, yet I'll most-likely be using 'em ala elm-chan's usage under that NEC chip, and elsewhere:
Rated for 260deg C, which is 500deg F, which seems a bit low... I usually use 600deg F on my iron, unless I'm soldering something *really big*, in which case I bump that dial up to 11. Still, $3 to give it a try, vs $50?! for a roll of kapton-tape... and if you don't pay attention to the tape's thermal-characteristics, (which I never did, before), might just well be rated for 500F... worth a try.
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Still holding off on "the big order", though, until I've had some time to make sure I haven't forgotten anything... Ideas?
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