Hi,
I wanted to learn about logic gates and how to use them (such as 74HC00 quad NAND gate) and I have found there is soooo many of different chips - HC, HCT, with or without Schmitt trigger, with open colector or totem pole outputs etc. When surfing internet I have found PLDs - ATF16v8 costs about $1 on eBay and I was very excited reading the datasheet: it can be programmed to behave like any gate chip - or more connected. But when I got to programming section there is just a note "Programming/erasing is performed using standard PLD programmers." I hoped I could use Arduino to program the chip (something like ArduinoISP) but it looks like there is no such option. The chip itself looks obsolete, even much newer (and more expensive) ATF750 is old. In fact I didn't find any programmer for such chips, just old discusions stating they are expensive ($100+; I would rather buy an oscilloscope) and DIY programmers are nearly impossible to make due to proprietary nature of programming protocols.
So does anyone know how to program ATF16v8 cheaply (around $10) - either DIY or some cheap programmer? If not is there some other chip that can be programmed to work as "low level ICs" (logic gates, latches...) easily and is cheap ($1-2) and is breadboard-friendly (I am able to solder 20 lead SOIC on adapter but I doubt I would be able to solder 144 leads FPGA).
If not I am afraid the cheapest way would be to buy a bag of different ICs to have available the one I currently need.
Thanks for any hint.
and I have found there is soooo many of different chips - HC, HCT, with or without Schmitt trigger, with open colector or totem pole outputs etc.
Well , yes, there are, but that never stopped anyone else from learning logic circuits.
Isn't that the whole point anyway ? (to learn how to design a circuit that anyone in the world can duplicate using inexpensive chips from ebay ?
Why do you need PLD technology ? Is your logic circuit that complex that it is not practical to do with discrete TTL or CMOS logic chips ?
raschemmel:
Why do you need PLD technology ? Is your logic circuit that complex that it is not practical to do with discrete TTL or CMOS logic chips ?
No, I just thought it would be much easier if I had a chip that can be any logic circuit I need. Currently I have just a quad NAND gate and hex inverter. I was planning to buy another circuits I might need and look what can be done with them - but I don't know what gate I will need. I was planning to try to replace MCUs in some simple projects with "discrete" logic - just to prove I can do it. But when I will find during tinkering I need a gate I didn't buy (i.e. 5 input NAND) it would be nice to be able to "create" it from PLD (and possibly replace with proper chip later) instead of building it from other chips.
As a benefit I would learn something about "ancient PLDs" which would hopefully give me some insight into modern FPGA.
Also making my own logic gate -> latch -> timer -> ? -> ALU -> ? -> ? -> simple microprocessor could teach me much if I manage to get so far.
Smajdalf:
No, I just thought it would be much easier if I had a chip that can be any logic circuit I need. Currently I have just a quad NAND gate
Then you've already got everything you need I guess.
Like Archimedes once said: "Give me a NAND chip large enough, and a breadboard on which to place it, and I will compute the universe."
I might be paraphrasing a bit. ;D
I've used FPGA's to do complex logic things - protocol generators/decoders for example.
Xylinx and Altera, to name just two - make excellent devices.
Not that cheap - and you'll have to learn Verilog or VHDL.
good stuff if you need 10,000 + gates
regards
Allan
Smajdalf:
Hi,
I wanted to learn about logic gates and how to use them (such as 74HC00 quad NAND gate) and I have found there is soooo many of different chips - HC, HCT, with or without Schmitt trigger, with open colector or totem pole outputs etc. When surfing internet I have found PLDs - ATF16v8 costs about $1 on eBay and I was very excited reading the datasheet: it can be programmed to behave like any gate chip - or more connected. But when I got to programming section there is just a note "Programming/erasing is performed using standard PLD programmers." I hoped I could use Arduino to program the chip (something like ArduinoISP) but it looks like there is no such option. The chip itself looks obsolete, even much newer (and more expensive) ATF750 is old. In fact I didn't find any programmer for such chips, just old discusions stating they are expensive ($100+; I would rather buy an oscilloscope) and DIY programmers are nearly impossible to make due to proprietary nature of programming protocols.
So does anyone know how to program ATF16v8 cheaply (around $10) - either DIY or some cheap programmer? If not is there some other chip that can be programmed to work as "low level ICs" (logic gates, latches...) easily and is cheap ($1-2) and is breadboard-friendly (I am able to solder 20 lead SOIC on adapter but I doubt I would be able to solder 144 leads FPGA).
If not I am afraid the cheapest way would be to buy a bag of different ICs to have available the one I currently need.
Thanks for any hint.
Logic chips have the same basic function.
The family of chip has varying characteristics related to logic levels and speed.
For learning basic CMOS is fine.
PLD's have many gates but require various ways to programme them.
They have many gates which gives great functionality.
What are you trying to achieve. ?
So does anyone know how to program ATF16v8 cheaply (around $10) - either DIY or some cheap programmer?
I don't know of any cheap programmers and the problem with building one is that you'll end up with a programmer that can only program 16V8's.
Jiggy-Ninja:
Like Archimedes once said: "Give me a NAND chip large enough, and a breadboard on which to place it, and I will compute the universe."I might be paraphrasing a bit. ;D
But I have currently only one NAND chip and I cannot use more than one table of space. I cannot afford build from discrete transistors as others do.
Boardburner2:
What are you trying to achieve. ?
There are many different logic gates - just NAND gates come in 2,3,4 or more inputs with different logic levels as I mentioned before. I just hoped instead of having bag full of circuits looking for the one I need (it is ever on the bottom) I would simply flash the circuit onto the PLD. It is even more difficult with more sofisticated circuits - counters are 4-24 (or more) bit, upcounting, downcounting, clocked on rising/falling edge, binary, BCD, decade, Johansson (or what was his name) etc. It would be nice to have one IC that can be programmed to anything of this by just pressing a button on a computer (after writing proper software).
Also I got impression FPGAs are (part of) future. Since I am afraid getting one and trying to understand it is similar to buying top tier Intel processor and trying to write a software for it I wanted to get some simple PLD - like learning AVR let me understand concepts used in "real computers".
Maybe I have chosen the wrong way and the whole idea of using PLDs to emulate basic circuits was nonsence because it looks like noone else is doing it.
But I have currently only one NAND chip and I cannot use more than one table of space. I cannot afford build from discrete transistors as others do.
Nobody uses discrete transistors anymore . They use 7400 family TTL or 4000 SERIES CMOS.
I am wondering if a logic simulator of some sort would be the answer , although i could not suggest one.
I am wondering if a logic simulator of some sort would be the answer , although i could not suggest one
As I understand it , the "issue" is real estate (not enough room for all the logic chips but my impression (without further information) is that the OP has little or no experience using 7400 family TTL or 4000 series CMOS.
Look for the tl866 device programmer. It handles some GALs, as well as a bunch of pre-serial-programming EPROM, FLASH, and microcontroller chips...
I find PLDs to be extremely power hungry compared to current logic families like 74HCxx. Depressingly so; that was swell when you could replace a half-dozen also-power-hungry 74xx chips, but nowdays not so much.
See if you can find a copy of Don Lancaster's "CMOS Cookbook" or "TTL Cookbook" at better-than-collectable prices. There's good info in those about combining old-style logic chips into useful circuits. https://www.amazon.com/exec/obidos/ISBN=0750699434/donlancastersgurA/
Nowadays, some microcontrollers (notably some of the 8bit PICs) include a few pins worth of PLD-like functionality. Microchip calls it "CLC" - configurable logic cell CLC: Configurable Logic Cell - Developer Help I think there is something similar on some Atmel chips, but I don't recall what they call it, or which chips have it (I'm pretty sure it's not on any of the common Arduino chips)
At lower speeds, you can probably program an AVR to act like nearly any logic circuit...
There days you would use 74HCxx series for 5V or 3.3V use, these are a fast CMOS with good noise
immunity.
For exclusive 3.3V supply you might want the low voltage families like LVC or LCX.
Smajdalf:
But when I got to programming section there is just a note "Programming/erasing is performed using standard PLD programmers." I hoped I could use Arduino to program the chip (something like ArduinoISP) but it looks like
It is difficult because the programming interface for some chips is not open.
You have to buy a programmer.
Its also an old chip if you look at CPLD they are In circuit programmable with minimal hardware required.
Some PAL can be programmed this way too.
Best to find an IC with in circuit programming facilities.
A search should find free programming software for this type of device but it will be windows based.
EDIT
I used to use PALASM which is now free to use.
Smajdalf:
Maybe I have chosen the wrong way and the whole idea of using PLDs to emulate basic circuits was nonsence because it looks like noone else is doing it.
Well i certainly used to do it, it is possible to replace/combine many different logic functions this way
There are hobbyist level FPGA boards and programming tools available for not a great deal of money. e.g. (CycloneII EP2C5T144 FPGA Development Board + ALTERA USB Blaster JTAG programmer). This one uses freely available design and simulation tools from Altera. The problem is learning the toolset is a non-trivial barrier to entry.
The idea of using software simulation tools rather than actual hardware has merit as well. There are many such tools including the full on development systems from Altera and such. The free demo version of SIMetrix/SIMPLIS does mixed analog and digital simulation and is as easy as any to get started with.
MrMark:
There are hobbyist level FPGA boards and programming tools available for not a great deal of money. e.g.
Yes but in my day the chips were available in through hole packages.
Not very available these days, really useful for breadboard applications if you can get them.
I sympathise with the op and can only suggest that he uses a simulator and then orders the chips for his project that he needs.
His idea seems good for a learning experience but availability of components these days does not seem to be good.
OK raschemmel - very impressive - but would you do it like that today? - especially if you had to produce 1000's of them ....
there's a difference between a one-off lash-up in a hurry and a reliable product
regards
Allan