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Re: LS/HCT/etc. logic familes
On 13/07/17 01:43, bitrex wrote:
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My Mac Plus still manages to load Smalltalk from 3.5" floppies.

I still have a 8" floppy drive; no idea whether it works, though.

Re: LS/HCT/etc. logic familes
On Thursday, 13 July 2017 01:43:38 UTC+1, bitrex  wrote:

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I remember using a dozen computers networked to a server that consisted of a dual 8" floppy to provide storage. A whopping 400k per disc IIRC. Years later we were wowed by a 70M HDD.

If we went back to then and told them about the computers we have I don't think they's believe it.


NT

Re: LS/HCT/etc. logic familes
On Wed, 12 Jul 2017 20:07:03 -0400, bitrex

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Dec sold a rackmount dual 8" floppy, a couple of hundred kilobytes per
drive, for the PDP-11. It cost over $3K.


--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: LS/HCT/etc. logic familes
On 07/12/2017 08:53 PM, John Larkin wrote:

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Woah it's 1975. Ok, let's go all in and rent a System 370 for $42,000/month!

Re: LS/HCT/etc. logic familes
On Monday, July 10, 2017 at 1:29:47 PM UTC-4, bitrex wrote:
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LS is completely irrelevant garbage. In its day it was a great replacement  
for standard TTL working at same speed but 1/3 the current consumption. Thi
s junk is for maintenance of existing old products and hobbyists. Dunno who
 would use it for a modern product.

Re: LS/HCT/etc. logic familes
On 07/10/2017 02:37 PM, snipped-for-privacy@gmail.com wrote:
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I use LS for hand-prototyping little hairball logic circuits sometimes  
because static sensitivity is less of an issue, and I've got a box full  
of 'em with just about ever part # represented

Re: LS/HCT/etc. logic familes
On 10/07/2017 20:21, bitrex wrote:
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Not just static sensitivity - apparently LSTTL is much rad-harder than  
cmos. But not making stuff that gets irradiated I haven't used LSTTL  
since the 1980s.

As others have written 4000 is still great when speed isn't needed but  
operating from rails above 5V is. Really useful for hairball interfacing  
to mickey-mouse analog and descrete circuits. At 15-18V Vdd CMOS can  
sink/source pretty hefty current!

I use plenty of analog switches like HC4051/52/53 and a few shift regs  
and counters but now hardly use any gate logic HC or LVC because  
microcontrollers are so cheap and flexible.

piglet

Re: LS/HCT/etc. logic familes
On Mon, 10 Jul 2017 15:21:57 -0400, bitrex

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Use LVC, or some variation.

Re: LS/HCT/etc. logic familes
bitrex wrote:

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Well, not new designs, but I still use 4000 chips in a PWM servo amp for  
brush motors that runs directly off 12 V, same as the FET gate drive supply.  
Makes things really simple.

I have a brushless servo amp that uses a Xilinx CPLD running off 3.3 V, so  
if the 4000 family eventually becomes unavailable, I could update the brush  
version to use the same.

I use a lot of CPLDs and FPGAs in the other stuff I design, so not much  
74xxx in anything now.  About the only thing else is voltage level  
translators and a 4538 one shot as a watchdog.

Jon

Re: LS/HCT/etc. logic familes
HC is alive and well.  5V isn't much used for logic anymore (if your  
functions aren't sucked up into an MCU or FPGA, you're wasting a ton of  
board space and probably parts cost*), but is great for glue logic, line  
drivers and receivers, etc.  Anything faster or newer (like LVC) is great  
for similar things at lower voltages (though, LVC is technically rated for  
5V!) and higher speeds.

*The threshold feels like somewhere around 0 to 4 logic chips.  Even if  
you're not using a bargain basement MCU, it gets very economical to use one  
to replace more than a few logic chips.  Even more so when you're talking  
about replacing more logic chips with a small FPGA.

LS is still around, but I certainly wouldn't use it for new designs.  CMOS  
is better in all respects, and HCT parts are available if you need the input  
threshold.

CD4000 is still around, and has no alternatives for high voltage logic --  
unless you want to cook your own from transistors!  It's unfortunate that  
it's so slow and gutless, but when you don't need fast logic and you're just  
gluing some things together in an analog circuit that doesn't even have a 5V  
supply: it's absolutely perfect.

As for packages, everything is available in DIP and SOIC.  (Heck, there  
might be fewer in DIP than SOIC, I'm not sure.  DIP is slowly going away,  
and you should be prepared for SMT!)  Some is also TSSOP, unfortunately the  
less common ones usually aren't.  CD4000 I think doesn't usually come in  
TSSOP.  Receivers like 74HC7014 aren't available in TSSOP.

Tim

--  
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
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Re: LS/HCT/etc. logic familes
On Mon, 10 Jul 2017 13:29:40 -0400, bitrex

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LS was slow and had terrible noise immunity and metastability. There's
no reason to use it in a new design. Not many people still make it.

HC/HCT is OK for general glue logic. Or the various TinyLogic parts.

I use HC (the schmitts are nice) and HCT, and some Tiny parts for
their speed. And some ECL and CML for extreme speed. Most "logic" is
in uPs and FPGAs now, so HCT type parts are mostly buffers and little
utility circuits.





--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: LS/HCT/etc. logic familes
On Mon, 10 Jul 2017 13:29:40 -0400, bitrex wrote:

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I use many shift registers such as the 74xx595 or '166 for low speed I/O  
expansion for microcontrollers and FPGAs.  

Oh, and a zillion SN74AVC16T245 for level shifting.

Allan

Re: LS/HCT/etc. logic familes
On 11 Jul 2017 10:21:32 GMT, Allan Herriman

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TPIC6595 is similar, but has zener-clamped open-drain power outputs.
It's a great relay or LED driver.



--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: LS/HCT/etc. logic familes
On Tue, 11 Jul 2017 08:17:02 -0700, John Larkin wrote:

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I sometimes use TLC59281RGE
http://www.ti.com/lit/pdf/sbvs139
It has 16 outputs, 17V open drain with resistor-programmed current  
limit.  It's a LED driver, but is quite ok for driving logic.

Allan

Re: LS/HCT/etc. logic familes
bitrex wrote on 7/10/2017 1:29 PM:
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This is an odd question.  Why do you care what others are using them for?  
LS and HCT logic come in two flavors, SSI/MSI and LSI.  The SSI/MSI devices  
would only be used in new designs that need a tiny amount of logic but are  
high volume to be very cost sensitive (a very small percentage of designs  
today).  The LSI devices such as bit slice, ALUs, etc., can be implemented  
easily in programmable logic likely at a lower cost and power.

So other and maintaining obsolete equipment there is very little demand in  
new designs for discrete logic.

I was working on a new design for a military radio once where they needed an  
SPI receiver to control a few I/Os, relays, etc.  This is just a couple of  
shift registers and a wee bit of random logic totaling some five or six very  
low cost devices in very small packages.  I was told to use an MCU so the  
design could be "flexible".  This required a crystal, the MCU, a power  
regulator, a reset chip, a programming interface,...  I am happy to use MCUs  
where they have an advantage, but this was one case where the function was  
very fixed and the MCU was a bit of a PITA.  But they already had some two  
dozen MCUs in the product, I guess what is one more?

--  

Rick C

Re: LS/HCT/etc. logic familes
On 07/11/2017 12:14 PM, rickman wrote:

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Why wouldn't I? Is it a bad plan to know how other people in the  
industry practice their trade? Why ask questions. Why do anything at  
all, I guess...

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Ok that was very informative, thank you :-)


Re: LS/HCT/etc. logic familes
On Tuesday, July 11, 2017 at 6:14:44 PM UTC+2, rickman wrote:
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Any decent low price microcontroller has all those functions inside, so that does not count. You sometimes need a pull-up for the reset pin, but that's all

Cheers

Klaus

Re: LS/HCT/etc. logic familes
Klaus Kragelund wrote on 7/11/2017 8:04 PM:
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Really?  They come with crystals and regulators and *reliable* reset  
controllers?  So you can drive an MCU from 12 volts with no other external  
components other than a resistor?  Wow, they've come a long way.

--  

Rick C

Re: LS/HCT/etc. logic familes
On 07/11/2017 09:23 PM, rickman wrote:

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Well, if all you have is 12 you'll need to bring that down to 5 or 3.3.  
But yeah an 8 pin chip like the ATTiny45 will work fine with just a  
supply bypass capacitor. It won't run as fast with the internal  
oscillator as compared to a crystal, but 8-12MHz is good enough for some  
tasks. The Tiny series has a reset pin but it isn't required for most  
normal operation; its fuses can be configured to give you simply 6 GPIOs.

There's also often plenty of code data space to flash a bootloader into  
even the little chips so you don't have to muck about with high voltage  
programming; the chip powers up with the bootloader ready to accept a  
serial transfer for a few seconds, if it gets the handshake it expects  
you can send the new code over regular TTL serial and the bootloader  
will flash it into program memory for you on the fly


Re: LS/HCT/etc. logic familes
On 07/12/2017 10:18 AM, bitrex wrote:
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This is an 8 pin AVR programmer:

<https://www.dropbox.com/s/abyhrpy2cbe2iuk/20170712_102249.jpg?dl=0

Plop chip in, connect to USB, hit Enter, wait 15 seconds, remove, plop  
into circuit

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