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dalbert02

Which pic?

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I am suffering from a bit of ignorance and I was hopeful that someone could help me out. I want to build some of RC-CAM's wonderful projects, but I am totally new to PICS. I just bought a PIC Programmer (Olimex USB w/ ZIF) and it seems to communicate just fine with Microchip's MPLAB Software. My problem or question is, what PIC chip do I buy? For example, take the PanCam project, it specifies a 12c509x chip. When I go to Mouser, I see a PIC12C509A but with the following suffixes: 04I/SN, 04/SN, 04I/P, 04/P, 04I/SM. Such as PIC12C509A-04I/SN. So which of the PIC12C509A chips do I buy?

Thanks,

-dave

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The suffixes denote temperature range and package. For hobby use, ignore the temperature performance. Just pick a PIC that has the package style you want (DIP, SOIC, etc.).

BTW, you can use the newer PIC12F508/509 instead. The PIC12F series are FLASH devices that can be re-used (don't let your chip programming system erase the factory written OSCAL value).

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Thank you. I read the spec sheets for each and now understand. I have always used DIPs and shy away from SMD so SOIC and DFN were new concepts.

-dave

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Well, after figuring what was necessary to program the flash part, and what oscal was all about I find that the Loma works but seems to detect a signal absence or power failure (on it's own) as it will never time out for the low power mode. MPLAB ICD2 allows looking at and changing the oscal value and this has been checked. Will the fact that the 12F part runs instructions at 200Ns and the 12C part 1Ms have any impact on the code execution? I am only using the part due to cost. I have a few of these to build for our club as we move from beans to corn next year and we fly a bit of combat. Having not built with the 12C, and if no correction need be made I will try some of the original spec parts to see what happens. Fred

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I find that the Loma works but seems to detect a signal absence or power failure (on it's own) as it will never time out for the low power mode.

I don't know what you mean; can you explain that in a different way? If you mean that the lost model beep cadence doesn't slow down after one hour of a continuously missing R/C signal, then that is odd.

Will the fact that the 12F part runs instructions at 200Ns and the 12C part 1Ms have any impact on the code execution?

Not likely. When using the internal osc, they are both 1-MIPS parts. They have the same instruction set and operate the same way. The only difference to the user is that the PIC12F can be reprogrammed.

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Situation is like the part gets an external reset mid-operation. The part gives the greeting tones and then sends the warble, other times after an hour gives the same number of warble sounds and never goes into low power mode. Within the hour you will hear the greeting tones. Before reply, I will be sending you a screen shot of MPLABs setup for programming the part. I have a question about the configuration bits. I think my setup might be incorrect. Fred (Getting aircraft ready for a Fly-In)

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I have included a screen shot in .pdf format to illistrate my questions. This is to headoff any doubt in the setup of MPLAB. (See Attached File)

Your instructions say "MCLR disabled", MPLAB only allows a selection of "Internal or External". I took your instructions to mean internal and glued up the first parts. No changeing them now. Did I assume correctly? (see screen shot) Another thing. If code protect is enabled does this render the 12F508 part un-eraseable?

Fred

Well maybe I won't incllude a file. The site will not allow this. If you want to see it..... send me a temp. email addr to send it to. The file is a bit big. (4.7m)

Edited by mrfx2001

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Internal reset (MCLR pin disabled) is correct. The PIC12F can be erased if code protected. Be sure to write down the OSCAL value of the factory blank part so that you can restore the value if the part is erased.

If your LoMA is resetting during use, that is, you randomly here it give its power-up "I'm alive" beep sequence, then it might be a power supply related problem. Beyond that, it is a mystery to me.

Attachments are allowed. The file size is limited, so to post a screenshot just reduce its size.

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I may be on to something here. I'll need to breakout the Techtronic. There is an issue with some solid state Rxvrs and the Futaba synth. I'll go back to a crystal driven module and see what happens, I'll know more sometime this week. What is the size limit on the attachment?

Fred

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File size is up to 120K. JPEGs set to 72 pixels/inch, with widths less than 600 pixels, are best.

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Well there ya go. A picture is worth a thousand words.

The 465B said the channel output from the receiver was bad. Another Rx confirmed the problem. I would have pulled my hair out trying to figure out the problem if the RX had made it to the aircraft. You need to add "RX Test Fixture" to the product Description. Thank you for your time and keep on thinking up these great projects. By thee way, anyone that states that they cannot hear the alert from a distance should be advised the project is not at fault. It works fine as long as it gets power. Maybe the problem is in there head. A kid’s toy might be the solution to the issue. Remember the big ear? A dish, microphone, transistor amp (modified with a band pass filter at the loma alert freq) a set of ear buds. This might overcome the ears deficiencies.

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Thanks for the update on your troubleshooting. It's good to hear it was resolved.

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Mr.RC-Cam

I think permission is much better than forgiveness. I am seeking the green light to use portions of the html on your website to be inserted in HRCFC's website explaining the operation and features of LoMA. The construction portion will be deleted and no other portions will be modified in any way. There will be no references to your website for dumb questions to be answered but will state that any problems should be directed to me. Any unique troubles will be directed to you from me. No outside access is available to the user area of the site. Only club members may access the information. Thanks.

Fred

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