FPGA Single LED Demos: FPGA board for a good ideas/suggestions

Hi Antti,

What about morse code to give the status?

I should have some code in VHDL which I will dig out and send to you,

Regards, Hans

Antti Lukats wrote:

Most obvious is to extend to a BiColour LED, Driven from 2 pins, so that you can generate : Pure RED, Modulated RED (OE), Pure GREEN, Modulated GREEN (OE) and Colour Modulated (PWM %R/100-% G) Control lines are : R, R.oe, G, G.oe

Then at eye-ball rates, you can signal something over 4 states, without needing long dividers.

[Well, yes, this is only partially vendor neutral: it works on all those vendors who actually gave this some thought, and installed a BiColour LED ]

My preferred modulation is PDM (Rate Multiplier), rather than PWM : PDM uses the least resource in CPLDs, and filters better in DAC applications.

Also not on your list, is a RC5 / manchester Encoded LED modulate. Target the std IR-Remote Receivers, perhaps with an IR led in Parallel if the RED energy is too low to activate a NearBy - StdIR RX unit.

That allows actual BIT serial (status flags) info to be sent, into a simple receiver.

One-Wire encoding is another way to send Freq tolerant information, in an easily decoded manner.

-jg

*) RS232 signaling sending something like "POST ok". Then you could just direct it to any laptop with ir-serial. Possibly IrDA. *) Morse code.

*) Maybe 10 Mbps ethernet is doable. Guess not thoe :-)

*) With an external mirror+stepper you could reflect the led light onto a paper and draw something.

With a more stable oscillator possibilities vastly increase.

contact at pb (a) ludd . luth DOT se

Best to then blink the Morse dots using PWM at 1KHz and 50% duty cycle so that you can also hear it with a solar cell and a piezo earpiece ;-)

Ben

"Hans" schrieb im Newsbeitrag news:h_%4g.4329$ snipped-for-privacy@newsfe5-gui.ntli.net...

Hi Hans,

yes VHDL based morse message could be added, I think I had something some while ago, but not sure if I can dig that out, so if you find I will look it.

I have been actve on short-waves ages ago so Morse of course popped up in my mind too, well its of course easier to implement with some small soft-core processor, but plain HDL version could also be a nice example

Antti

.- -. - - .-

.-- . .-. . -.-- --- ..- .- .... .- -- ..--..

.- ..- -.... ...- ..-

"Austin Lesea" schrieb im Newsbeitrag news:e32s8f$ snipped-for-privacy@xco-news.xilinx.com...

ROTFL !

i did think f**** windows has trouble refreshing screen, so I closed and opened this email many times. in the hope it would display the fonts properly - morse code !!!

A N T T A W E R E Y O U A H A M ? A U 6 V U

uh? I probably need morse-classes to decode the message properly :)

Antti

HAHA - I was going to reply that the LED is SMD 0603 so connecting beeper in parallel would not make sense, but then hum solar cell !!

hum, interesting would it actually work? I bet not the solar cell possible would not deliver AC or would it? I am almost tempted to test!

well the LED on board will be possible cheapest one available (around 0.01 USD from HK) so it will not have many mcd, but the LED + solar cell idea is something that could be even used for some weird application.

Antti

dual color SMD led costs 10 times as much as single color and the layout isnt so standard and I have some pre-series PCBs with only one LED already. Sure dual color LED would have more possibilities for visual effects

could you elaborate on this? I had delta-sigma DAC already on my list that is pulse density modulation - but you are referring to something else?

Actually one-wire comm requires known frequency reference better than I can count for, also in my requirements was no other interface (than LED)

I was possible giving not enough information at first place - the module in question has actually 3 interfaces with 6+6+4 (shared with JTAG pins in parallel) I/O's one of them can be used for block transfers to host with up to 6MByte/S

However any communication with host would require some software on the host what may not exist for the host platform, so I was looking for demos that can be 'tested' for simple 'it blinks, ít works' in the case we assume there host communication is unavailable - similarly any demos requirying additional hardware ae beyound the scope, dual color, tri-color led buzzer, IR tranceiver are all things that could be used, - with extra add-on modules.

I was more looking for more ideas to demonstrate things that an FPGA can do, it could be some algorithm that is processed once or in a look and if the self check result is ok then blink a led.

Just to have people a way to 'seeing is beliving' want to test this or that, download this, when LED blinks then it is signal that this or that works - in real hardware.

Antti

But costs a tiny fraction of the PCB / FPGA price, which is what actually matters ?

It is probably the same thing, if your delta-sigma is PDM. I am used to delta-sigma having a feedback loop of some sort, so I avoid that term. The PDM we use is the same as the venerable Rate Multipliers ( 4089, 4527 IIRC) and they use one PT per resolution bit. PWM compares need two, unless hand-coded.

You would use optical pickup, so are outside the "Mk1 EyeBall", but the functions can be stacked on the LED. One wire systems are usually PWM coded, so autobaud ?

Always a good idea.

-jg

Some twenty-five years ago I used to be able to 'hear' the brightness on the television by the volume of the 50Hz hum if I pointed a solar cell at the screen at close range (10-20cm). The solar cell was a cheap single-cell thingie bought at Tandy/Radio Shack, so if solar cell efficiency has made any sort of improvement in the last quarter-century, this might actually be viable.

Best regards,

Ben

See

The code is very basic but should give you an idea how to put something together quickly :-)

Regards, Hans (G7... too long ago to remember my callsign :-)

On a sunny day (Mon, 01 May 2006 12:40:56 GMT) it happened "Hans" wrote in :

If you use an IR LED, you can have the FPGA change channels on the TV. I had an IR LED on the PC par port for a long time, and a photo transistor too. I recorded the remote control signals (just zero / ones) in a few kHz sampling loop. Then had a bitfile for ch1, ch2 ch3 etc. to start the VHS from the PC.

It seems in the US you can set the traffic lights to green too.

Maybe use the LED for some kind of user /input/?!

I recently came across this article (from 2003),

Kolja

--
mr. kolja waschk - haubach-39 - 22765 hh - germany
fon +49 40 889130-34 - fax -35 - http://www.ixo.de

...and found again where:

(has some more links regarding using LEDs as sensors)

Antti Lukats schrieb: [..]

[..] [..]

I miss the obvious timeshare of your led. eg. 1s divided clock followed by 1s "clock stable" status followed by whatever useful state comes out of your design. I used similar technics to get 24 bits on 4 LEDs visible. Serialise some information and display it a measureable amount of time with remarkable start/end of data (blinking seems for better than stable signal for this task) would be the best for 1 LED.

bye Thomas

"Antti Lukats" escribió en el mensaje news:e31q3u$s6d$ snipped-for-privacy@online.de...

Pseudo random LED blinking using LFSRs at a very low frequency

Josep Durán

Just blink the led quickly 5(say) times with a small pause between the next 5. To indicate that section 3 has failed extend the length of blink 3 by 3 or 4 times.

colin

Thanks Kolja,

I have known that LEDs are actually bidirectional, but the links pointed out are great! fortunatly I aldready have my LED wired up to FPGA so that it can support the "LED sensor" mode so I defenetly will at leat try it out

Antti