Numbers and Letters After PIC Number

[kiwipiper]

Greetings Everyone,

As a bit of an introduction, I am from New Zealand and I am very new to programming PIC's. I purchased a bunch of stuff from Reynolds Electronics including the PicBasic Pro USB Bundle and a Serial LCD Display Module. Cost an arm an a leg to get the stuff delivered to New Zealand and then Customs wanted some more money. Hopefully it will all be worth it.

Must say it was a bit of mission working out how everything fitted together. It is not for the faint hearted. Anyway finally figured it out (I think) and did manage to get an LED to flash on an off so must be somewhat on the right track.

So now on to bigger and better things. My plan is to start with some of the projects at rentron.com. The first project I have decided to start with is "Reading ROM Codes From 1-Wire Devices" because I have some iButtons. The project said I need a PIC16F877 microcontroller so I go to order one here in New Zealand and I get a big list of options:

So my first silly question is: When I search for a pic to purchase I see letters and numbers after the PIC here are some examples:

PIC16F877-04/L
PIC16F877-04/P
PIC16F877-04/PQ
PIC16F877-04/PT
PIC16F877-20/L
PIC16F877-20/P
PIC16F877-20/PQ
PIC16F877-20/PT

Question: What are the numbers and letters and which one should I purchase?

Thanks in advance. Cheers Bruce

[Wilson]

Don't buy any of them.
Have a look at the data sheet. Microchip suggests using 16F877A

The letters indicate package type.

[Jumper]

Hi,

You should be aware that the 16F877 is old, it has been replaced by the 877A that is slightly different but it is more or less the same PIC. But if you start from scratch and a few cents more or less makes no difference I would suggest a 18F4555 (it has usb if you want to try later on) or 18F4620 which is more or less a supercharged 16F877. More RAM more ROM and a lot more gizmos and gadgets inside for later use.

The letters after -P -PT and so on are what package they are in. For beginners -P is a good option. It is a standard hole-mounted package and will fit into lab-boards and similar. The others are surface mounted and are not suitable for lab use at all.

All this -P and -PT stuff can be found in the end of the datasheet for the PIC. You will need this datasheet so download it and save it.

Go for the 18-series and you will not be limited in either codespace or speed in the near future :-)

/me

[kiwipiper]

Thanks very much for the advice it was very useful to me. I have ordered a few 18F4620's to get me started as the place I get this stuff from in New Zealand has those available. It doesn't seem to stock the 18F4555 which I might try and get as well as I am particularity interested in communicating directly with a computer. However, I have heard USB can be a bit tricky to start with.

[Bruce]

And if you need any help getting the example you found on our site converted over to your
18F part, just give me a shout....;o}

I'll walk you through the whole process.

[SteveB]

Kiwipiper,
Welcom to the Forum and the wonderful world of PICs and Pic Basic Pro.

I think Jumper might have mis-typed the USB part number. Look for 18F4550.

And if you need any help getting the example you found on our site converted over to your
18F part, just give me a shout....;o}

I'll walk you through the whole process.

This exemplifies the best part of this forum. Many gracious and helpful people, who are also very skilled and knowledgable.

Also, be careful, this can be additicive. Although better than most addictions, it can result in lack of sleep, strange (or other) looks from loved ones and friends, and in the worst of cases, negligence in more important life issues. Enjoy in moderation!

SteveB

p.s. There is also a 18F4455, identical to the 18F4550, except for less memory.

[Jumper]

Of course it was a typo, or actually it was a matter of not really bothering to read what it said on the chip on my table properly.. and I can't even blame it on beer this time.

/me