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Inexpensive way to try out GALs?

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7 hours ago, matthew180 said:


We are all in the past here. :)


It is hard to convey intent with text, so my comment probably came across a little wrong.  I agree with you, and I like to imagine using just enough technology to solve the problem.  However, that is getting harder and harder to do, and we find ourselves in a situation where the smallest, cheapest, and best supported (software and vendors) solutions are battle axes with 1000x more capability than needed.

That's okay, I figured we were in agreement.  I'm sure what I "say" (type) sometimes seems odd.

7 hours ago, matthew180 said:

Want to blink and LED?  Get a 133MHz MCP with USB interface, download a 500MB IDE onto your 8GB operating system, fight with USB drivers, download an I/O library and a framework, find the right location in a 100 line "simple example" template, write 3 lines of code, compile, upload to your MCU, reset and bask in the glory of a blinking LED.

You're describing my experience with the "Make: AVR programming" book!  It uses an Arduino as an alternative to a naked AVR chip.  I'm glad the guy includes a C library and instructions for using it.  I got as far as flashing some LEDs before getting sidetracked.

7 hours ago, matthew180 said:

That crap drives me nuts!  But that is how things are now.  Going against the grain is painful (I do it all the time, and I'm probably very miserable for it).

You're not alone.  Just look at the current contents of the "Off-Topic" conversation about new cars and televisions


But I digress...  Back to the topic of GALs, I have a T48 and some ATF units on order from Jameco.  It'll be fascinating!




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8 hours ago, hhos said:

Trivia that isn't on topic: I don't think most EPROMs would be fast enough to do that, but Williams Electronics used some smaller, very fast memories to strobe pixels to the screen in their video games.  They are 7489s,74189s, etc.  Also, for the cocktail tables models there was a larger one that gave line numbers so flipping one bit in the hardware flipped the entire display around to the player on the opposite side. 🙂  The 74LS612 is another example of this used primarily for memory management. (Super AMS)


Reminds me of this ZX Spectrum recreation without custom chips (no ULA in this case). He's using EPROMs to generate the pixel and sync info:


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  • 4 weeks later...

Had success with my first attempt at programming a GAL tonight!

I produced a 28-pin single-bit inverter, with a current draw of 70mA.  Then I tried a 3-input NAND gate.  At first I thought it didn't work; after wiring-up my test fixture (breadboard and an LED) properly, it worked too!

I'll have to build-up to the more-complicated logic I'll need.



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