VGA Connector - Prof. Dev. Board

ApteryxOz

Hi guys, don't seem to be able to get it to work with any of the demo VGA objects available. Done some fault finding with a scope and meter. The signals seem to be on the V,H and BGR pins ok, but no 5 volts - this seems a bit strange. There doesn't seem to be a circuit path from pin 9 VGA to the 5 volt supply. Is this correct?

I have tried the pin 16-> 23 and 8->15 to V,H,B1,B0,G1,G0,R1,R0 using the VGA64 Tilemap Engine and the VGA High-Res Text Driver with pin sets referneced as per the spin files. Signal at VGA pins, no 5 volts and monitor wont pick it up. I have tested the monitor on my lap top - all ok. (Samsung Syncmaster 173V)

Any pointers would be appreciated.

Regards
ApteryxOz

Toby Seckshund

The 5 Volts on PIN 9 is there so that an EEPROM in the monitor can be read by "Plug n play" OSs. The Prop never uses it. Sometimes, on non compliant wiring, the middle row of the 15 Pin is all grounded and that would short out the 5 Volts.

The usual reason for no VGA is that the H and V syncs are the wrong way around, the H is on P13 (half way, on the bottom row) or the monitor doesn't like the frequency of one/both of them.

ApteryxOz

thanks for the info re:5v pin.

No joy on H vs. V pins. Have tried 800 x 600 and 1024 x 768 no joy. Could it be refresh rate? Have tried:

'{' 1024 x 768 @ 57Hz settings: 128 x 64 characters

hp = 1024 'horizontal pixels
vp = 768 'vertical pixels
hf = 16 'horizontal front porch pixels
hs = 96 'horizontal sync pixels
hb = 176 'horizontal back porch pixels
vf = 1 'vertical front porch lines
vs = 3 'vertical sync lines
vb = 28 'vertical back porch lines
hn = 1 'horizontal normal sync state (0|1)
vn = 1 'vertical normal sync state (0|1)
pr = 60 'pixel rate in MHz at 80MHz system clock (5MHz granularity)
'}

{' 800 x 600 @ 75Hz settings: 100 x 50 characters

hp = 800 'horizontal pixels
vp = 600 'vertical pixels
hf = 40 'horizontal front porch pixels
hs = 128 'horizontal sync pixels
hb = 88 'horizontal back porch pixels
vf = 1 'vertical front porch lines
vs = 4 'vertical sync lines
vb = 23 'vertical back porch lines
hn = 0 'horizontal normal sync state (0|1)
vn = 0 'vertical normal sync state (0|1)
pr = 50 'pixel rate in MHz at 80MHz system clock (5MHz granularity)
'}

{' 640 x 480 @ 69Hz settings: 80 x 40 characters

hp = 640 'horizontal pixels
vp = 480 'vertical pixels
hf = 24 'horizontal front porch pixels
hs = 40 'horizontal sync pixels
hb = 128 'horizontal back porch pixels
vf = 9 'vertical front porch lines
vs = 3 'vertical sync lines
vb = 28 'vertical back porch lines
hn = 1 'horizontal normal sync state (0|1)
vn = 1 'vertical normal sync state (0|1)
pr = 30 'pixel rate in MHz at 80MHz system clock (5MHz granularity)
}

' columns and rows

Toby Seckshund

I assume that you have the "usual" 5MHz Xtal, with x 16 PLL.

ApteryxOz

yes, and am sticking to using:

''* File: GUIDemo.spin *
''* Author: Allen Marincak *
''* Copyright (c) 2009 Allen Marincak.

The keyboard and mouse seem to respond to the demo app (Caps lock, num lock etc. and mouse "lights" up)

will borrow a monitor from next door and try that as well

Toby Seckshund

I won't get a chance to fire up my demo board until this afternoon, but I am sure that I have tried that code before.

Back in the good old days at least the glass monitors would display something, even if it was a bunch of zig-zags.

ApteryxOz

new monitor says "No Input Signal" and goes to sleep.

I have:

P16 -> V
P17 -> H
P18 -> B1
P19 -> B0
P20 -> G1
P21 -> G0
P22 -> R1
P23 -> R0
P24 -> Mouse Data
P25 -> Mouse Clk
P26 -> Keyboard Data
P27 -> Keyboard Clock
5v -> PS/2 5V Rail
3.3v -> PS/2 3.3V Rail

ApteryxOz

Appreciate your help Toby. I like the Prop. Demo. Board so far. I think I will do some hard core stuff on it :-)

kuroneko

Odd, the schematic claims that there is a 5VDC connection. That said, I checked my board and there really isn't one. However, it is connected on the demoboard (which plays just fine with my monitor). So - for the sake of argument - could you fake a connection to see if that is the (only) issue?

ApteryxOz

Toby explains that above. It seems it is a "red herring" - used for Plug and Play hence not required. :-)

Toby Seckshund

That is my understanding of it, I never connect it on my stuff and nothing has objected to it, yet.

I haven't got that version the DemoBoard you are using, I made a clone of the plain DemoBoard.

Have you tried to swap around the two sync wires? No harm will come of it.

Pins 1,2,3 are RGB _ Pin 4 is O/C _ Pins 5,6,7,8,10 are Ground (Pin 9 is O/C) _ Pins 11,12 are O/C _ Pin 13 is H Sync _ Pin 14 is V Sync _ Pin 15 is O/C

http://pinouts.ru/Video/VGA15_pinout.shtml

ApteryxOz

I tried swapping over the V and H sync, no change.

Unless I'm misinterpreting something, I have the connections as they recommend in the texts (see post #7). I have a REV A board, but I can't see how that might affect things. I have scoped the pins as connected and that shows that the sync data and RGB signals are at the connector. I am stumped as to why it does not work :-(

I have tried some unrelated code (Audio, LED, button code, and so forth) and that all seems ok.

I wish I had a CRT display to check it on ......

BTW - I am restricted to pins 14,13,1,2,3 as the connector is part of the board. 6,7,8,10,5 are GND, 4,9,11,12,15 are NC

I wonder if it makes a significant difference which way round B1 and B0 are? (and R1/0, G1/0) will try that out tomorrow both with V and H swapped and "unswapped"

ApteryxOz

Looking closely at the cct diagram for the proffessional board, I see that connector x17 is:

V,H,B1,B0,G1,G0,R1,R0 which would map to pins 16,17,19,18,21,20,23,22

Will try this and get back to you soon

ApteryxOz

no joy. Measurments as follows:

V = ~60 hz H = ~32khz 3 volt signal

RGB seems good also 3 V signal

Toby Seckshund

The signals out will be 3 Volts until the 75 Ohms of the monitor is attatched, so thats all ok. The sync terminations are not so defined, sometimes they are 75 too, but often higher. Again that should be ok..

The H and V freqs are right for VGA so the monitor should wake up

kwinn

ApteryxOz, have you scoped the signals on the monitor end of the cable (assuming it is not hard wired to the monitor) to be sure the signals are arriving there on the correct pins?

ApteryxOz

Good point. Will try this

kuroneko

ApteryxOz wrote: »

Toby explains that above. It seems it is a "red herring" - used for Plug and Play hence not required. :-)

Maybe, maybe not. My laptop produces 5VDC on pin 9 (as does my demoboard). You mentioned that the monitor works fine on your laptop. The manual for the 173V tells me it's plug-and-play capable. So what if it actually requires 5VDC to be present on pin 9? I'm not saying this is the solution but one surely shouldn't ignore the possibility ...

ApteryxOz

tried this and no change :-( Have tried two monitors (HP and Samsung - nogo) . Maybe it is a Professional Board Issue. Can't see how though. Am hunting down another VGA cable just to discount it.

ApteryxOz

changing cable also had the same response. Well that's it really. Changed monitors, tested on a pc, changed VGA cable, tried 5V PnP line, ensured propeller pins attached to correctyy VGA pins:

V,H,B1,B0,G1,G0,R1,R0 which would map to pins 16,17,19,18,21,20,23,22

looks like it just wont work :-(((((

Bill Henning

Did you verify that your propeller is running at 80Mhz?

Did you try a different cog - perhaps the video pll's are burned out?

Did you try a different propeller chip?

Did you hook up Vcc and Vss on both sides of the prop?

Did you put decoupling capacitors (minimum 100nF on each side of the prop between Vdd and Vss)?

ApteryxOz wrote: »

tried this and no change :-( Have tried two monitors (HP and Samsung - nogo) . Maybe it is a Professional Board Issue. Can't see how though. Am hunting down another VGA cable just to discount it.

kwinn

This really shouldn't be that hard a problem to troubleshoot.

1 – Make sure you have a good common (ground) connection through the cable between the prop board and the monitor. This is very important since it is the reference for all the signals. The PC and monitor are connected by a common ground via the power line. This may not be the case for the prop board.

2 – Set your PC up to output VGA. Connect the monitor(s) and cable(s) in question to your PC and see if you get an image. If so the cable and monitor are good.

3 – Scope the signals on the monitor end of the cable and note the waveform and levels for reference. Check the +5V pin!!!!

4 – Connect the known good cable without the monitor to the prop board. Scope the signals at the monitor end of the cable and compare them to the results in #3. The voltages may be higher (or lower) due to the monitor terminating resistors not being connected but the timing and wave shape should be very close. Check the +5V pin!!!!!!

Make sure the H & V sync signals low level is at or very close to 0V!!!!!

If the signals and +5V are similar for the PC and prop you should get an image from the prop.

Make sure you have a common connection between the prop Vss and the monitor ground. The wall warts generally used to power these things do not usually have a ground connection.

ApteryxOz

Thanks guys. I have a Prefessional Dev Board, so all his hard wired. I only have access to RGB H V so I am ssuming the rest is covered. 5v does not exist on pin 9 of the VGA even though the Prop Board cct dia says it does, however, I have soldered it in to make up for it.

Both monitors and cables work on my Laptop. Scoping the output shows RGB H V are coming from the Propreller so the plls are ok. (I have a 200mhz scope :-) )

Will compare Laptop output to that of the Prop and see where that goes, will also look at the GND idea.

Many thanks for the assistance.

ApteryxOz

Have solved the issue now. The resistor R103 is incorrectly mounted and there is also no continuity from the VGA Plug side of R103 and pin 13 of the VGA Plug.

SMD resistor R103 did not have a solder lug at one end, hence there was no way that was gonna work anyway. So much for quality control !!!!

I must admit to being VERY peeved. I have wasted so much time on this - i don't get time on hobbies very often.

Any way- problem solved (After I get another SMD resistor to replace it and put a wire link from there to pin 13 of the VGA connector)

Overall score out of 10 - don't want to say - lets just say I am dissapointed with my Professional Development Board that I splashed out for.

dandreae

I apologize for your inconvenience, this is not a typical issue with the board. Please let us know if there is anything that we can do to rectify the situation? I realize you are located in Australia, however, we do have a distributor in Australia that can help us with any replacements that you may need if you are interested? Please feel free to contact me at dandreae@parallax.com and I will take care of your requests. Once again, I apologize for the inconvenience.

Kind regards,

Dave

Toby Seckshund

Hey, it good that there was a real reason for all this anguish.. Annoying, perhaps, but now that there is a cure go for it.

Whilst you did not wish for this "trial" it at least shows that this company, and forum, leaps into help (and no, I don't work for them).

Alan.

ApteryxOz

Hi Guys,

Yes, MANY thanks for the assistance :-) I won't let this little glitch get in the way of a good thing.

Dave, no need mate, but thanks for the offer. I undertsand the world is far from perfect and there are always times when "stuff" happens regardless of how hard we try to avoid it.

I am a little embarassed I did not find it earlier - I am a bit rusty - Ex-Avionics Engineer.

After I have had some more time to familiarise myself with everything, I plan to spend some time with XBee Tx/Rx and the 802.15.4 spec. It looks as though the XBee 802.15.4 Starter Kit is the way to go. Will save up and get one :-)

In the mean time, I think I will stick with a text console and setup some commands to create RF output by command and design (or steal a design) a modulator and PA to suit. Eventually I want to use this setip to experiment with Tesla Coils as Plasma Speakers. I have some other ideas for an RF Sweep Generator and associated result monitoring - could be fun :-)

Again thanks for your help.

BTW - how do I change this thread to "Solved"?

potatohead

I think you can edit your first post.

Toby Seckshund

ApteryxOz

If you are wanting to build a RF sweep genny then be aware that the output of the counters have a fair degree of jitter which is dependant on the number of LSB 1's (you might be thinking of using a separate chip of course)