Where can I get some PIC...

falleafd said:

Nigel,

I see that the PROPIC2 programmer is the same to your programmer (I saw the schems). So may I use your programmer with ICPROG? Because ICPRO works quite good under XP, and you said winpicprog has some problems with XP?

So I should choose David Tait hardware of ICPROG to program for your 16PRO40?

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Yes, you can use ICProg, I set it to 'ProPic2' for the P16PRO40.

But WinPicProg works fine under XP, I fixed the bug a good while back now - although I still don't know what caused it, basically something perfectly legal under 95/98 and ME won't work under NT based Windows, but only the first time you run it? - strange or what?.

Some more questions,

I'm a little bit confuse about PIC memory. With HC12, I had access to 2K onboard volatile memory, and another 2K non-volatile from an EEPROM extension.

I looked at microchip's website, where memory is divided into three types: flash, opt, rom. I don't quite understand the difference between them. I know that there is an UV-erasable type that takes 20 min to erase. What's the advantage of using this type over regular EEPROM PIC?

Anyways, what I want is a couple PIC with EEPROM (for development and testing), and a load of cheaper PIC with write-once only memory (for finished project)

Oh My god, nigel, your winpicprog work perfectly in my PC. Well, oki, i'm building your programmer right now and test with it, I'll tell you the result (on my PC, because it worked good all over the world) next week. That is, disasm is good, no error warned with parallel port. I didn't test with programmer, but i feel it oki. Can we test the port without the programmer?

I used chippie's programmer for long time, and don't want to change because it works good too, and there was no power supply needed. But I think I should try your programmer. Thanks muchie.

phoenixy said:

Some more questions,

I'm a little bit confuse about PIC memory. With HC12, I had access to 2K onboard volatile memory, and another 2K non-volatile from an EEPROM extension.

Click to expand...

For a start you need to understand a PIC is a totally different type of processor, is uses Harvard architecture, which means program memory and data memory are totally seperate - unlike most other processors.

Typical memory would be 1K or 2K program memory - 14 bit for a midrange PIC, where all instructions (35 of them) are a single word long.

Data memory is usually only 40-50 bytes, known as working registers.

Many PIC's include a small area of non-volatile EEPROM memory as well, usually 64 bytes upwards.

I looked at microchip's website, where memory is divided into three types: flash, opt, rom. I don't quite understand the difference between them. I know that there is an UV-erasable type that takes 20 min to erase. What's the advantage of using this type over regular EEPROM PIC?

Click to expand...

FLASH/EEPROM are both easily eraseable, and can be re-programmed in a few seconds. UV-eraseable types, as you say, take a fair while to erase under UV. OTP types are the same as UV-eraseable, but without the window to erase them.

Historically there was only one EEPROM PIC, the 16C84, all others were OTP or UV-eraseable.

There's very little advantage in OTP chips now, the extended range of FLASH and EEPROM based PIC's is really taking over from them - with the current exception of a chip with built-in USB.

Anyways, what I want is a couple PIC with EEPROM (for development and testing), and a load of cheaper PIC with write-once only memory (for finished project)

Click to expand...

The FLASH/EEPROM chips aren't much more expensive, you may as well stick to those - I would suggest the 16F628 and 16F876/7 are good choices, have a look at my tutorials for examples.

thanks for the great response!