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:: EPE Chat Zone ≠:: ≠Radio Bygones Message Board :: » EPE Forum Archives 2005-2006 » Archive through 06 April, 2006 » More on FPGA's « Previous Next »

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Obiwan
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Username: Obiwan

Post Number: 333
Registered: 12-2005

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Posted on Friday, 31 March, 2006 - 11:18 pm:   Edit Post Delete Post Print Post

The more I read about these things, the more I want to investigate using them. It looks like the best way to make a LCD controller among other things.

(those LCD's that don't have a controller built in, like the backlit 640x480 from Allelectronics for $11 or maybe the LCD's from laptops)

You can get a smaller dev board for about $70 and up from the manufacturer of the FPGA's.

But I didn't know that Parallax also sells them!

http://www.parallax.com/html_pages/products/altera/smartpacks.asp

It turns out that Parallax was using FPGA's to develop a new processor that they are now (or very close to) selling. In the process of using the FPGA's, they decided to offer them as a dev board to their "Stamp" users.

Now they have pretty much, or have finished the design on the new chip that they were working on.

It's basically 8 32 bit processors in one microcontroller. This is also well worth looking into by itself. It's called the "Propeller", because it has a hub that sort of rotates like a propeller, that communicates to all the other sub processors. Looks like a VERY cool chip too.

The chip has basic RAM (8Kx32) and basic ROM (8Kx32) and a bus controller and config/Flags etc..., and that communicates with one of 8 sub-processors that has it's own scratch pad RAM, processor, video generator! 2 "I/O Assistants", I/O register and Direction flag set and about 32 I/O pins. Looks pretty dang fast too, like up to about 80Mhz.

http://www.parallax.com/propeller/index.asp

Anyway, those that are interested in the FPGA's may want to check out the Parallax site as a way to get started, I'm not sure which way I'm going.

And some of you may also want to check out that Propeller Chip as well, it looks very promising.

I just got a subscription to another magazine and they have a big article on it, so I'll be doing some reading on it and report back to you on it if anybody is interested. (the Propeller, not the FPGA's, I'm still working on those)

I think Mr. John Becker could go a little bonkers with this chip! (Oh yeah, the chip is on $25 too, devl kit is about $150)
May the Force be with (most of) you.....
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Mikehibbett
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Post Number: 379
Registered: 04-2005

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Posted on Friday, 31 March, 2006 - 11:45 pm:   Edit Post Delete Post Print Post

I'd be interest to know if anyone else would be interested in a cheap FPGA dev board. We use cyclones a lot at work and have been considering spinning a cheap dev kit ( in the UK )

Might make an interesting article...

Mike.
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Obiwan
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Post Number: 334
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Posted on Friday, 31 March, 2006 - 11:50 pm:   Edit Post Delete Post Print Post

I would like one.

Make that a BIG! Checking the pricing on Parallax, they are anywhere from $150 or so, to almost $500!!! Forget that! I can get one cheaper than that on the site that was first posted on PFGA's here, www.fpga4fun.com (or his sales site)

Makes that Propeller chip look even better! Man, I knew their prices were not the best, but damn!

Right now, I'm going to be doing some readoing up on them, getting some software, looking at projects and stuff, then I'll be looking for a Dev board.

But I'm guessing that one way or another that I will be using them, no matter what. So might as well jump in. (but looking before I leap)

oh yeah , it should be pointed out that these are NOT the same as the old PAL chips that were out there a while back. I guess that's one reason I haven't thought about them more than I have, I thought they were more like PAL's than anything else, and I didn't think I'd ever be using those.

But there's still a lot of learning to find out exactly what it IS (and how best to use it)

And since the Propeller has a video generator in it (8 of 'em), that just might be a better choice for a LCD controller than a FPGA. Don't know yet. Cost is an issue too.

(Message edited by obiwan on 31 March, 2006)

(Message edited by obiwan on 01 April, 2006)
May the Force be with (most of) you.....
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Mikehibbett
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Post Number: 380
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Posted on Saturday, 01 April, 2006 - 12:46 am:   Edit Post Delete Post Print Post

I would use the cyclone, just because I can get them .

I have an Xilinx development board that was quite cheap - $75 I think, in the US. Fortunately I have a relative who works in Xilinx and I got one at a rather reduced price :o)

My personal interest is in soft CPU cores. I always fancied building my own, but was put off by the idea of wiring up several hundred logic gates. It hasnt stopped others though. for example:
http://www.homebrewcpu.com/
you can connect to this guys ttl wonder.
telnet magic-1.org
ops, digressing a bit. It's a nice system to play with though. It has a port of the original adventure on it.

Mike
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www.drivesentinel.co.uk - Home build GPS Speed Camera Detectors
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John_becker
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Post Number: 209
Registered: 05-2005

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Posted on Saturday, 01 April, 2006 - 01:11 am:   Edit Post Delete Post Print Post

Bonkers eh Mike? Take a really exceptional product to tempt me away from PICs (but I'm not totally closed to the idea!). Too much off-topic I guess to discuss in PnM. You might try asking Editor Mike if he'd be interested in a short intro feature on them, or I'll do it for you if you send me a brief summary privately.

(Just lamenting the fact that the latest RS CD-ROM cat is not suited to browsing for products for use in a new design. I'm finding it gets more difficult each time. Trying to find an octal buffer that's got chip enable and capable of handling up to 140mA to 200mA per pin, for a multiplexed LED display I'm working on. Thought I'd find something in the ULN range or similar. Can I find one? Not on your nelly :-(

J
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Obiwan
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Post Number: 335
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Posted on Saturday, 01 April, 2006 - 04:10 am:   Edit Post Delete Post Print Post

John, think of this as a PIC on Steroids.

Instead of one pic in that chip, you've got 8 doing 8 different things at one time.

Sort of like Windows(I know....) for PICs.

I'm thinking of your chip, seems like there should be one out there, but that's a lot of current per pin so I'm not sure about it.
May the Force be with (most of) you.....
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John_becker
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Post Number: 210
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Posted on Saturday, 01 April, 2006 - 09:38 am:   Edit Post Delete Post Print Post

A splendid way to put it George!. I reckon Mike H & I should persuade Mike K we think it's worthwhile highlighting for readers through our pages. Looking at the web pages Mike H links, it looks interesting.

Re the "other chip", I agree it's a fair bit to ask, but what I'm thinking of doing is a moving message display using many leds, modular in batches of 5x7 per character, using dot-matrix led displays to minimise soldering (and to provide for all ascii characters plus simple graphics, maybe 6 or 8 characters per module. Horizontally (rows) per module there'd only ever be one led on at a time due to the multiplexing, at say 20mA each. Vertically (columns) though there could be up to 7 leds on at a time, a total of 140mA, plus a margin. I dont want to use multiple power transistors and am hoping to find suitable chips to use for the job, with chip select control.

J
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John_becker
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Post Number: 211
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Posted on Saturday, 01 April, 2006 - 09:40 am:   Edit Post Delete Post Print Post

Sorry George, it's the pages you highlight that I refer to!
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Mikehibbett
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Post Number: 381
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Posted on Saturday, 01 April, 2006 - 09:41 am:   Edit Post Delete Post Print Post

I have exactly the same problem John, especially with Farnel. Fortunately we have the catalogues at work, but I have noticed that the cheaper products dont get into the paper edition. Try looking for a SPST momentary switch. You'll eventually find one for 7p on the farnel website. Cheapest in the catalogue is about 60p.

FPGAs will have to wait a while, maybe next year. If it is still possible to buy them with leads then :o)
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John_becker
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Post Number: 212
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Posted on Saturday, 01 April, 2006 - 09:44 am:   Edit Post Delete Post Print Post

Thanks Mike, I'll look into them. J
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Older__wiserish
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Post Number: 3
Registered: 03-2006

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Posted on Saturday, 01 April, 2006 - 04:52 pm:   Edit Post Delete Post Print Post

Hate to advertise for the opposition but E**kt** have just started a series Feb or Mar issue I think, not my cup of tea but it looks quite interesting
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Obiwan
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Post Number: 338
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Posted on Saturday, 01 April, 2006 - 07:20 pm:   Edit Post Delete Post Print Post

That's ok Mr. John Becker, I thought he posted some links as well. And I'm no glory hog, doesn't bother me any.

I think the problem with that other chip, is the total disapation. If you don't mind using a few more chips, Microchip has a nice "buffer" chip. TC4467 or similar. You might be able to find an octal MOS driver out there, look at line driver or MOS FET driver.
May the Force be with (most of) you.....
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John_becker
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Post Number: 213
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Posted on Sunday, 02 April, 2006 - 01:07 am:   Edit Post Delete Post Print Post

After looking at various block diagrams of the options during the day, at present I think I may be better to use a cheap PIC (eg 628) to control the 35 leds in each matrix module. They're only about £2 or so each, and will control all 35 leds without resorting to interface chips for complex multiplexing. Such multiplex techniques would add chips, add pcb space and take longer to assemble. And not a lot of price difference I reckon to simply PICing each led module. These PICs will also have enough pins to communicate with the next PIC in line, ideal it seems to scrolling messages. So that's what I'll examine more closely (of course Propellor technology might be superior to even this technique, but I'm not yet ready to learn about it, until someone shows me the way. Let others be the tutors for once ---)

Sorry to have made this a side issue to the true thread!

(Oh, George, absolutely no need to give me titles, John'll do nicely ta if you feel so inclined :-)

J
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Obiwan
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Post Number: 343
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Posted on Sunday, 02 April, 2006 - 02:07 am:   Edit Post Delete Post Print Post

This sounds a lot like something Mr. Paul Goodson was working on, or wanted to work on.

A while back, Futurlec had some really nice Dot Matrix display modules. I thought they were smaller so I ordered 10 of them. Turns out they're are 2 inches tall! Dual color too. And very cheap, just over a buck each I think. Very nice displays.

Red/Green bi-color, 5x8 and 8x8, $1.90.
http://www.futurlec.com/LEDMatrix.shtml

But no pin out. But just about anybody could figure that part out. I'm tempted to purchase some more if they still have them. It would make a really nice moving sign. I bought them to display things like address and data for a micro. But they're FAR too big for that.

Thank you John. Or Mr. B!

Oh, no problem on the topic, it will go where it wants. If people are interested in FPGA's, it will go there, if they're interested in the propeller, it will go there as well.

And speaking of Futurlec, they have a GREAT deal on motor control chips too. The LM629 that goes for anywhere from $35 or so to almos $60 for $19.90. And it's companion H-Bridge driver (nice one) for $9.95, those are $20 parts as well.

You can create some really nice, powerful, smart, precision motor controls from those bad boys.

I just got some samples and was getting ready to order some. Boy I'm glad I saw that!!

See? Off topic can be a good thing!

(Message edited by obiwan on 02 April, 2006)
May the Force be with (most of) you.....
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John_becker
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Post Number: 214
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Posted on Sunday, 02 April, 2006 - 09:21 am:   Edit Post Delete Post Print Post

George, 2" 5x7 matrix is the size I'm intending to use, probably from Rapid in the UK at UK£ 1.70 each for 25 off. Rapid's cat (2002 edition I have here at home) is in a muddle over pinouts, but RS Components seem to do the same devices (but more expensive) and they quote Kingbright part numbers TA20-11EWA (common anode) and TC20-11EWA (common cathode). The commoning refers to the column connections. I pulled in their datasheets from Kingbright's site via Google, which clarified the pinouts, which are the same for each device:

C1 pin 13, C2 p3, C3 p4 & p11, C4 p10, C5 p6

R1 p9, R2 p14, R3 p8, R4 P5 & p12, R5 p1, R6 p7, R7 p2.

The pins on the devices, viewed as from the front: Top line 14 to 8, Bot line 7 to 1

Forward voltage for red is 2.1V, with minor diffs for other cols. Forward current 20mA.

Hope that helps. I'll look at the site you quote.

J (Herr Lord Baron Johann von Dessau! - just joking - paternal grandfather was from Dessau, Germany, married an English lass, about 100yrs ago :-)
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John_becker
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Post Number: 215
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Posted on Sunday, 02 April, 2006 - 11:33 am:   Edit Post Delete Post Print Post

George, I've just found I didn't get those datasheets from Kingbright (whose site I found difficult) but through

http://www.datasheetarchive.com

a useful site for free datasheets

John
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Obiwan
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Post Number: 349
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Posted on Monday, 03 April, 2006 - 07:23 pm:   Edit Post Delete Post Print Post

The displays I have are a bit different, 10 pins on top and bottom.

There is one pin per row that connects to V+, then you have two pins per column, one for red, and one for green that connect to ground.

I haven't decided if that's good or bad yet. Momre pins to control it for dual color, that's for sure.

But I think it would let you mix the red and green better to get other colors. And they have nice color/brightness at 5 to 10mA per.

And they said they were looking into a FPGA dev board also, if I hadn't already mentioned it. But no date.
May the Force be with (most of) you.....

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