Two questions in one....and a request to Parallax
SamMishal
Posts: 468
I have just started playing with the Demo Board.
·
1- The microphone works perfectly and the quality of the play back is quite good.
····this brings me to my request for Parallax....
····· I tried to replicate the microphone circuitry on the PPDP and failed abysmally
····· I think it is due to the fact that I did not have exactly the right microphone....but...also...
····· due to the interference of the Bread board.
····· My request is twofold:
········· a- can you give us a part number from say DigiKey or another supplier for the exact mic you used
········· b- is there any possibility you may supply a mic add on like you do for the PS2 and RCA and VGA components?
··········c-·(yeah I cannot count··
) can you also do the same for SD card holders????
·
2- My second point is actually a problem.
··· The demo board comes preloaded with a nice demo program that shows a nice graphics through the TV RCA output.
··· When I view the demo on a TV the displayed graphics are clipped at the top and bottom….is this normal? What is the
···· solution? Is it perhaps because the demo is meant for a VGA rather than a TV??
·
Another point is an appeal tot he masses.....I remember seeing a while back a third party supplier for SD card
adapters that can be used with a Breadboard like in the PPDB....I cannot now remember who.
Can someone please point me to the right web site?
Samuel
·
1- The microphone works perfectly and the quality of the play back is quite good.
····this brings me to my request for Parallax....
····· I tried to replicate the microphone circuitry on the PPDP and failed abysmally
····· I think it is due to the fact that I did not have exactly the right microphone....but...also...
····· due to the interference of the Bread board.
····· My request is twofold:
········· a- can you give us a part number from say DigiKey or another supplier for the exact mic you used
········· b- is there any possibility you may supply a mic add on like you do for the PS2 and RCA and VGA components?
··········c-·(yeah I cannot count··
) can you also do the same for SD card holders????·
2- My second point is actually a problem.
··· The demo board comes preloaded with a nice demo program that shows a nice graphics through the TV RCA output.
··· When I view the demo on a TV the displayed graphics are clipped at the top and bottom….is this normal? What is the
···· solution? Is it perhaps because the demo is meant for a VGA rather than a TV??
·
Another point is an appeal tot he masses.....I remember seeing a while back a third party supplier for SD card
adapters that can be used with a Breadboard like in the PPDB....I cannot now remember who.
Can someone please point me to the right web site?
Samuel
Comments
Sparkfun·has a few to choose from as well as a few that are supplied·by contributors to the forum, there was a recent one that eludes me right now. It's in his sig.
Jim
Thanks again....this is not the one I was looking for....but it will do if no one else remembers the other one.
The one I remember had the pins all ready to just insert into the breadboard. The one you pointed me to
would do but I need to solder pins to it....its price is nice though.....
Thanks
Sam
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Dave Ratcliff· N6YEE
(C'mon, this sales pitch had better work....
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Quit buying all those fixed voltage regulators, and·get an Adjustable Power Supply·for your projects!· Includes an LED testing terminal!
*-NEW-* SD Card Adapter·Now available!· Add extra memory to your next Propeller project with ease!
On the question about the Mic. I've never included a Mic on any SpinStudio modules, I had thought that it was infrequently used on the DemoBoard and didn't think it would draw much attention. Am I wrong? do I need to include a Mic on the Audio/Video board?
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Brian
uController.com - home of SpinStudio - the modular Development system for the Propeller
PropNIC - Add ethernet ability to your Propeller! PropJoy - Plug in a joystick and play some games!
SD card Adapter - mass storage for the masses Audio/Video adapter add composite video and sound to your Proto Board
http://www.ucontroller.com/
is the one I was looking for. The price is good too and it is already assembled
and ready for use.....that is a good deal and since you say you have used it and
it worked for you I am definitely going to buy it.....thanks
Vaati....
the one you pointed is good too....however, it needs assembling and it is not cheaper....
but it does look like fun to put together......Thanks
Thanks all for your prompt replies.......
Samuel
·
Yes I like your SD card holder and will be buying it soon.
·
Regarding the microphone.....it would be great if you did an add on
just like you do for the SD card holder....pins all ready to insert into the breadboard
or even it would be nicer if the pins were arranged so as to insert directly into the
header for the I/O pins on the PPDB but then the Vdd and Gnd would have to be staggered
so as to be also insertable into the breadboard .... would be an awkward arrangement but would
avoid breadboard capacitance etc.
·
Samuel
·
So you are saying the Demo board preloaded demo actually is meant to be clipping
since it is also doing the graphics simultaneously on a VGA?? I thought that might be the case.
I have not yet tried it with a VGA but does it also clip on the VGA?
Sam
·
The Game Stacker looks good....can it be inserted into a breadboard or is it just for the Spinstudio ?
Samuel
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Brian
uController.com - home of SpinStudio - the modular Development system for the Propeller
PropNIC - Add ethernet ability to your Propeller! PropJoy - Plug in a joystick and play some games!
SD card Adapter - mass storage for the masses Audio/Video adapter add composite video and sound to your Proto Board
I tried all this and made up a small PCB and soldered everything and
plugged it directly into the headers for the I/O pins but it still did not work.
I am guessing the mic I used was not right.....but you are saying that any electret mic would work???
The setup on the Demo board works GREAT but mine was abysmal.....but I am not the best solderer around....
Maybe some shielding for the whole setup is required???
Samuel
·
WM-64PNT is the Digikey part number for the box of mics I grabbed from the freebie table at UPEW.
Rich H
I would guess that the type of mic you are using either doesn't have any gain or enought gain.
The type of Electret mic to use should have amplifacition built in.
The Electret mic that W9GFO listed has a FET built into it. WM-64PNT is the Digikey part number
If you look athe the demo board schematic you will see a connection from the mic to vdd
Typical supply pin labeling
BJT -- FET
VCC -- VDD -- V+ VS+ Positive supply voltage
VEE -- VSS -- V− VS− Negative supply voltage
Demoboard Schematic
www.parallax.com/dl/docs/prod/prop/PropDemoDschem.pdf
FET mic
industrial.panasonic.com/www-data/pdf/ABA5000/ABA5000CE11.pdf
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Aka: CosmicBob
Post Edited (Bob Lawrence (VE1RLL)) : 7/30/2009 2:34:38 AM GMT
Rich H
Andy did a lab for the breadboard-based PE Kit using a microphone from Radio Shack. If you go to the Propeller Education Kit Labs sticky-thread at the top of this forum, scroll down and you will see an Applications section. Under that there's a heading for Propeller + PC applications for Viewport. The second project there, for Oscilloscope & Spectrum Analyzer, has a link to a thread where he posts the microphone circuit and RadioShack part number and link to their site.
Maybe that will help?
-Steph
With the PE Kit, I had to use 100 pF caps instead of the Propeller Demo Board's 1 nF caps for the sigma-delta ADC because of the extra capacitance contributed by the breadboard clips.·
It's optimal to use cog zero's counter module with P7 and P8 for input and feedback pins on the sigma-delta ADC circuit if you are running the application at 80 MHz. Or, use cog 7 and P23 and P24. At 40 MHz, it doesn't matter which cog or I/O pins you use. The signals from cog zero have to propagate through fewer OR gates to get to the I/O pins, and P7 and P8 are also closest to cog 0. Likewise with cog 7 and I/O pins P23..P24. See Cog and I/O Pin Relationship in the Propeller Datasheet for more information.
Even though the ViewPort example uses cog 2, when the ADC gets moved from P16 and P19 to P7 and P8, the signal has to pass through three gates instead of six to get to the I/O pins, and it really does make a noticeable difference at 80 MHz. Again, at 40 Mhz, it doesn't matter which I/O pins you use for the sigma-delta ADC circuit, so long as other parts of the application can all function at that speed. I haven't updated the docs in the PE Kit application Stephanie referred to, but all you have to do is move the circuit to P7 and P8 and update the I/O pin numbers in the application's CON block accordingly.
Andy
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Andy Lindsay
Education Department
Parallax, Inc.
Post Edited (Andy Lindsay (Parallax)) : 7/30/2009 6:45:50 PM GMT
That CERTAINLY helps a lot.....I have established that INDEED I was using the wrong mic for the circuit as given
in the Demo Board Schematic........I wish I knew about the thread you pointed to before I already soldered the mic....
Well, I am now going to buy·another mic and try the circuit as given in the thread.
I do have one question though.....
In the schematic given for the Demo board is P8·the In_Pin and is P9 the FB_Pin ????
The program microphone_to_headphones.spin works with the Demo board and uses P8 and P9
so if I am to make this program work with the radio-shack mic as given in the circuit in the thread
I will need to change
·· either the program to work with P16 and P19
or
·· change the pinout in the circuit to P8 and P9
I am assuming the radio-shack circuit uses P16 and P19 with·2 pin separation·to avoid pin cross talk.....
So I am going to asssume that it is better to change microphone_to_headphones.spin·to use P16 and P19....
BUT......the question is which pin corresponds to which pin?
Is P8 the In_Pin and P9 the FB_Pin so I need to change microphone_to_headphones.spin to use P19 instead of P8
and P16 instead of P9..............or is it the other way round??????
From comparing the radio-shack circuit and the Demo board one and also from studying the program·I think it should be
P8 -> p19 (IN_Pin)
P9 -> P16 (FB_Pin)
am I right?????
Thanks a lot for the help
Samuel
P.S. I am going to build the circuit as given in the thread you pointed me to and I hope it works
as well as the one in the Demo board......I will report back here when I do have a result.
P.P.S.· I must have been writing while Andy was doing so too.....
So now I am more confused!!!!
Post Edited (SamMishal) : 7/30/2009 7:26:45 PM GMT
OK......in microphone_to_headphones.spin the following lines have to be changed to ????? to make it work
with the breadboard and radioshack circuit??
············· movs····· ctra,#8························ 'POS W/FEEDBACK mode for CTRA
············· movd····· ctra,#9
············· movi····· ctra,#%01001_000
············· mov······ frqa,#1
the #8 should be #7 and the #9 should be #8 ???????????????
and which one is the IN_Pin and which is the FB_Pin???????????
Please help????
Sam
Jonathan
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lonesock
Piranha are people too.
MOVS CTRA, #input_pin
MOVD CTRA, #feedback_pin
To understand how this works, take a look at the first two tables in CTR.spin in the Propeller library. The CTRA module's APIN field is bits 5..0, and POS detector w/feedback mode says that APIN is not an output. So it's the input pin. Likewise, the BPIN field is bits 14..9, and it's the feedback pin, delivering !A1 (the NOT·of the previous value at the input pin).
Next, check out MOVS and MOVD in the Propeller Manual. MOVS CTRA, #input_pin copies the input pin value to bits 8..0 of a register, CTRA in this case. Conveniently, bits 8..6 of CTRA are unused, so nothing gets overwritten there. MOVD CTRA, #feedback_pin copies the I/O pin value to bits 17..9 of CTRA. Again, conveniently, bits 22..15 are unused, so it doesn't overwrite any other important bit fields in CTRA, and the BPIN field receives the·correct value.
Andy
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Andy Lindsay
Education Department
Parallax, Inc.
Post Edited (Andy Lindsay (Parallax)) : 7/30/2009 8:31:57 PM GMT
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Andy Lindsay
Education Department
Parallax, Inc.
If you are just trying out microphones_to_headphones.spin on the Propeller Professional Development Board, the circuit and code probably don't need to be modified. Just get that mic from Radio Shack and build up the circuit. If it doesn't work with 1 nF caps, try 100 pF caps.
If you do end up modifying the ADC circuit, there's one extra thing you'll have to change in addition to the MOVS and MOVD commands. The I/O outputs would also need to change in this declaration:
asm_dira long $00000E00
Any bit that corresponds with an I/O pin that the cog needs as an output needs to be set here.
Andy
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Andy Lindsay
Education Department
Parallax, Inc.
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I did try the circuit as given by the Demo Board schematic (1nF) and it did not work at all. Mainly I think due to
the bread board capacitance and also due to the mic being not the right one.
·
I·noticed that the pull up on the mic with the radio shack version uses 5V while the filtering and sigma delta part
uses 3.3V. In the Demo board·schematic they both used 3.3V and I built my PCB accordingly.
·
In any case, I am going to build the new schematic on the bread board using the 100 pF and the combo of 5 and 3.3V
with the·radio shack mic·(I'm buying·a new one tomorrow) and I will modify microphones_to_headphones.spin to use the
P7 and P8 as you mentioned and also the asm_dir (thanks for the heads up on that) and I will see how it goes.
and since I know what to do with the program now I can even change it to P16 and P19.....I will try all.....and
hopefully one version will work as fine as the Demo board version.
·
It would be great to know that the mic·can work on the PPDB and that a·beginner experimenter can just bread board it
and get it working.
·
Also the Sigma Delta ADC is a good thing to be able to work with, not just for sound and be able to ADC other signals
too....(with the same bandwidth of course).
·
So my efforts to get it working on the PPDB are worth it even though the Demo Board is also great.
·
The PPDB is a VERSATILE Experimentation Platform for the Propeller....VEPP if you will...
accept·that the Sigma Delta ADC could not be done on it......
·
Sam
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