nAst1: Progress and Concepts Thread

[robertisaar]

well, it doesn't run a program, but it is programmed, which sounds like some modern equivalent of a turing machine... ?

where should i start looking up how these things work(and how they're programmed)? i don't suppose it would be something as simple as this?

IF ADDRESS >$2000, CONTINUE, ELSE CLEAR BIT
IF ADDRESS <$8000, CONTINUE, ELSE CLEAR BIT
SET BIT

[brian89gp]

Yes, somewhat. Except you are thinking in a serial CPU way. Different method to the same result.

4:1 mux in VHDL. The 2 bit address select is a good example of address bus decoding.

http://vhdlguru.blogspot.com/2010/03/simple-4-1-multiplexer-using-case.html

And Verilog examples.

http://www.ece.ncsu.edu/asic/lect_NTU/AppendixA.pdf

[robertisaar]

looking at the VHDL link, it seems like you draw the circuits and it creates code based off of it? that doesn't seem like it would be too bad.

[brian89gp]

VHDL/Verilog = "the" circuit

There is no CPU in a CPLD (though you could program a CPLD to act as a CPU http://www.bigmessowires.com/cpu-in-a-cpld/) so there is no code to run, in serial, and to loop through. The CPLD 'program' is the actual hardware circuitry of all the gates and interconnections.

A CPLD is a simplified version of a FPGA if that helps any.

I can't remember the mode but you have the option of drawing the circuit diagram directly that you want to program into it. VHDL and Verilog are abstractions on top of that. A CPLD program is a circuit of AND/OR/NOR/NAND/etc gates. Think of a CPLD as a programmable replacement of 74HC00 logic chips, where you would pick various different 74HC00 chips for the correct gates and wire them together, instead, with a CPLD you would just program it with the same combination of gates.

I wish I could find what I was messing with in Verilog but I've seem to have misplaced it.

[robertisaar]

i'm going to need to do more reading... if they work the way i think they do, then it really isn't that difficult to get the results i would want out of it.

if they don't, then i'm pretty much treading water.

[brian89gp]

Finally found it. Schematic entry is what it is called, the type of programming where you draw the actual electric schematic and gate logic (instead of piecing it together with 74HC00 logic gate IC's) This could replace the functions of the U4 and U8 address decoder IC's for the 2k SRAM, the 4k SRAM mod by Montecarslow, the schematic above, etc.

The Xilinx XC3572XL has 5v tolerant IO pins and Atmel has a range of 5v CPLD devices.

Has a XC9572XL dev board as well as a couple simple examples:

http://dangerousprototypes.com/docs/CPLD:_Complex_programmable_logic_devices

[ericjon262]

Originally posted by Fierobsessed:

Figured something out the other day... Gm's flex fuel composition sensors output signal is compatible with the unused MAF signal input on the 1227730 ECM. So...

http://www.fiero.nl/forum/Forum3/HTML/000143-13.html#lastpost

[ericjon262]

went junk yard hopping for a 9396, and didn't have any luck, but I did find a similar PCM, so I picked it up for shits and giggles. it's a 16197409, from out of a 94 Lumina 3.1. I couldn't find anything out about it, any ideas? I'm gonna start ordering connectors, pins, and wire to make this thing work. I want to see what this car will do, but I also don't want to be limited to 6400 rpm like the obd2 bits limit me too. I'm also very interested in flex fuel, so if you're down for the challenge, I'm willing to be the test bed, and data log it for review.

[robertisaar]

a 94 lumina w/3.1 should be a rebadged 9396(definitely if it was a 4T60E car and not a 3T40).... probably a change to some EMI filtering components or something along those lines.

[ericjon262]

a 94 lumina w/3.1 should be a rebadged 9396(definitely if it was a 4T60E car and not a 3T40).... probably a change to some EMI filtering components or something along those lines.

cool, thanks!

[ericjon262]

any updates here? I'm sitting on a very poorly built fence, I'm extremely tempted to ditch the obd2 stuff I've got and go obd1, the biggest thing keeping me on the obd2 side is that I already have a flashtool/scanner.

[robertisaar]

no real progress, what time I've had to play with any code projects has been trying to get the boost patch for the 94-95 3100/3.4RWD PCM operating correctly.