If you have a 68332 'going spare' for this, then your approach is prety spot on. You could check the streams to see if repeat-pattern was common enough to encode.
- and you could define the count via a dictionary/table as well. [eg 5 bit index into 32 x 16 bit values ]
10 ohms would be a practical upper limit for anything I would need.
Up to this point, I would be happy with an analog movement with a logarithmic scale.
Could we say 200 mV peak to peak, open circuit, from a 10 ohm source?
I think there are clips that make two contacts, one on each side of the contact point. That makes in circuit, 4 terminal operation practical, if we can find or construct them.
That might be the toughest spec to meet, unless the initial hook up is always a discharge period, and you then push a button to excite the measurement. Still probably the most complicated part of the design.
Just green, yellow and red sections on that analog scale.
Well, the problem is that there's a dichotomy (or maybe a trichotomy) in the wish lists.
First we have the service tech's unit:
- range up to 10 or 100 ohms with 0.01 resolution
- measurement frequency the equivalent of 100kHz
- no need to distinguish between impedance and ESR
- accuracy is of little importance, 10% is more than good enough, we are looking for order of magnitude changes
- must be able to measure in-circuit, and preferably without concern about polarity, so voltage should be low (say < 200mV) and current should be 50-100mA RMS maximum.
- two wire probe is probably all that's practical, we have to beat the convenience of tacking a known-good cap across the part and trying it out
- it's reasonable to expect the meter to survive connection to a large capacitor charged to ~400VDC without complaint
- should be simple/cheap/reliable/rugged and easy to use
- a "Pike" model is possible that would analyze the cap and deliver a go/no-go indication (or possibly two for low-Z and regular caps)
Then we have the SMPS designer's unit:
-
Best regards, Spehro Pefhany
--
"it\'s the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
(oops, I guess ^N with the wrong window in focus will do that)
- 0.001 ohm resolution
- reasonable accuracy (say 1% or better)
- must measure actual ESR
- able to measure relatively low value ceramic caps as well as e-caps
- Kelvin measurement
- variable frequency measurement (maybe 100Hz to 1MHz)
- milliohmmeter for inductors
- no need for in-circuit but should not be damaged by cap charged to ~50V
- reasonable cost
and hey, if we're dreaming
- complex and real impedance of inductors, resistors and caps over that range
- ditto with DC bias on capacitors 0-10V and current on inductors 0-2A
Ideally, perhaps, kind of like a low-accuracy version of this guy:
formatting link
Best regards, Spehro Pefhany
--
"it\'s the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Here's a byte histogram of a typical Spartan 3 config file. Most of the config bits are zero. I read one Xilinx appnote about the rad hardness of sram-based FPGAs, and they got the upset rate calculation down by noting that most config bits actually don't matter!
I wrote the following two small C programs in 2001 for an Altera FPGA. You can't get it much simpler, and from a whole bunch of config files it gets about a 50% compression factor (plus or minus 15%).
You may need to set the 'most-common value' from 0x00 to 0xff - I don't have a lot of Xilinx bitstreams here to check what's best.
You could actually check the 'golden' bitstream to count which byte value occurs the most...
That's interesting. It only squeezes long runs of zero bytes, but then that's what you see in the Xilinx config files, too. It could also be tweaked to do 0xFF's, but I'd have to check to see if that results in net compression. A singular 0 (or FF) actually expands to two bytes!
Two things I don't like: 1) no date on your webpage postings like this one, 2) no price, etc. If it's in early preproduction stages, the page should say so. If not, it should give further info, or links, as would a bona fide product.
I like to see some individualism in the mix. A contest isn't a bad start, because someone posts their beauty, and it's dissected, with criticism and some improvements suggested, and it evolves, and finally we get something truly honed and perhaps even elegant. Watch and learn if that's your preference but it's better to take part.
I like your idea of posting functional circuit pieces, I'll use that for my circuit. It's an adaptation of a design by Len Cox, from SiliconChip's Circuit Notebook,
Work is writing manuals, writing test procedures, doing BOMs, solving customer problems, marketing, meeting with financial droids, cleaning my office. Designing is fun!
Dunno, the way you've said you write manuals sounds a lot like design. ;-) Writing test procedures can be some fun, if done the same way. The rest of that crap is for the boss to do (and a clean office is the mark of a sick mind). ;-))
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