Dangerous Prototypes

Other projects => Past projects => CPLD programmable logic => Topic started by: michu on April 12, 2012, 09:01:15 pm

Title: Now what?
Post by: michu on April 12, 2012, 09:01:15 pm
Hey guys

I just bought a XC2C64A CoolRunner-II CPLD development board, now what? What did you guys use this CPLD for?

I never worked with one, so I'm curious.

What I want to do is to create a kind of buffer chip for a spi/i2c signal (software schmitt trigger?), what do you think, is this possible? or completely the wrong approach?

cheers
michu
Title: Re: Now what?
Post by: robots on April 12, 2012, 09:21:07 pm
My future project is going to be a "switch" for multiple serial lines. One serial peripheral, for multiple devices (GPS, Radio control, etc)
Title: Re: Now what?
Post by: grimmjaw on April 14, 2012, 09:08:32 pm
second that....just bough mine today. wondering  also what cool project can be done with cool board
Title: Re: Now what?
Post by: BrentBXR on April 14, 2012, 09:40:18 pm
CPLD's are really sweet to use inbetween other projects; and really sweet for hacking. The CPLD (programable logic device- im sure can be used for more; but i use it for) you can signal A and minipulate it to output a signal X; thats what I use it for. I dont think CPLD's are really supposed to be used to run projects or anything; i think FPGA's are more for that.

much like the latest generation (in dev) bus blaster. They took an FTDI chip; connected all its pins to a large CPLD; then connected a bunch of headers to other CPLD pins. So now you can manipulate the FTDI signals in any way you wish; so when the signal comes out of the headers it can emulate multiple protocols and differnt proprietary jtag modes and such... not to mention uart, spi, and everything else the FTDi chips support.

I have been learning FPGA's too; and let me tell you... FPGA's are powerfull as fuck! Hard to use, very complicated; but can blow any microcontroller out of the water... that being said for everyday projects its easier and cheaper to use micro-controllers of course... but for that one off beast; I enjoy to utilize my custom FPGA development board.
Title: Re: Now what?
Post by: Xykon on June 20, 2012, 04:19:11 pm
I also just got my board a few days ago. I'm simply planning it to have some customizable logic available... like when I need a hex inverter, and/or/xor gates or multiplexer, I don't have to buy a bunch of chips first but can put it all on one chip and even make some adjustments on the fly if needed. Plus I wouldn't waste unneeded logic gates on a 74. I think that's exactly what cpld's have been made for, put together your own personal 74 series chip combining functionality from a whole bunch of chips into one neat little package.

If you are "simply" looking for a switch between different serial devices, have a look at this one: Serial/Analog Mux/Demux - 74HC4052 (http://http://www.sparkfun.com/products/9907)  It's a LOT cheaper than the CPLD board... unless you need a little cache to store incoming messages while listening on a different device... not sure if that can be done with a cpld but it might be an interesting project.

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