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JasonC

Which PIC

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I'm looking in the digikey catalog and I see they offer the PIC12C508 in both EPROM and OTP, from what I read either should work assuming my programmers supports them. Is this correct. OTP is my preference as they are considerably cheaper. Is OTP the "normal" type of PIC, ie should I assume this is what people mean unless they specify otherwise? Thanks.

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I would suggest you look at either the 12F508 or the 12F509 -- these are flash versions. Microchip indicates that the code for the OTP series is fully portable to the corresponding flash series. This has been my experience to date. The F series is rated at 100,000 cycles with a retention period of around 40 years. The advantages are ease of reprogramming -- if your code is hosed, you don't end up with an unusable chip -- just erase and reprogram. Secondly, the flash series is initially less expensive than the OTP -- much more in the long run since chips may be reused.

If your programmer supports the F chips, you might as well go with the 509 -- it is a few pennies more and doubles your available code space.

Microchip (www.microchip.com) has extensive data sheets for all their chips. You can buy sticks of 25 units (12F509) from Digikey at .93/chip.

http://dkc3.digikey.com/PDF/T051/0343.pdf

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Thanks alot. Do you have any recommendations for a Do it Yourself or inexpensive programmer that will handle the f type chips?

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I have no recommendations, per se, but I can give you information about the programmer I am using and why I chose it.

The programmer is manufactured by OLIMEX in Bulgaria and is distributed thru Spark Fun Electronics (www.sparkfun.com) in the States. Price is $86.95. The SKU# is PIC-MCP-USB. This is a USB powered programmer, no external power required, ICSP capable with ZIF socket. The firmware for the programmer is in a removable PIC16F876A and may be upgraded as additional chips are released by MicroChip. It is fully compatiable with MPLAB's PICSTART PLUS programmer and is recognized by MPLAB as a PICSTART PLUS.

My reasons for choosing this programmer were:

(1) USB only (since the majority of chips I burn are flash, I was not too concerned about the USB lacking sufficient power to effectively program the OTP's). No external power supply or bulky serial or parallel plugs.

(2) Upgradable firmware (OLIMEX has provisions for downloading firmware, burning an updated 16F876A, then replacing the existing on-board chip -- or you can buy the PIC with upgraded firmware for a $1 more from SparkFun).

(3) Fully compatiable with MPLAB V7.01

(4) The current list of supported PIC's was more extensive than other programmers I investigated.

(5) USB drivers were available and supported thru FTDI

(6) Documentation was available thru OLIMEX and SparkFun

The board is clean and well made with a combination of SMT and thru-hole components - it installed easily and has functioned without problem. There was some discussion on the SparkFun forum about the board not always being recognized as a USB device, but I have not had that experience.

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I found a cheap PIC programmer, it is USB and only supports flash chips and a limited numbr of them at that, but it does support the 12f508, used in many of the RC-CAM projects, and best of all, it is only $36 US, plus it comes with some tutorials, etc. Here is a link http://www.microchip.com/stellent/idcplg?I...ocName=en010053

This seems like a great deal if you are at all interested in developing your own PIC applications. It's also available from digikey for the same price

If you are really cheap / broke you can build the JDM programmer for next to nothing

here is a link to that http://www.jdm.homepage.dk/newpic.htm

Edited by JasonC

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