PIC16 series and PIC 18

[oakkathebest]

In doing clock project, why people use PIC16 instead of PIC 18? Is there any peculiar features of PIC 16?

[BobK]

Hello Oak,

Have you worked with PICs before? If not, then you might want to start with a 16F to get your feet wet then work your way up.

If you search our forum here you will find several examples of clock programs. Some will even work with an 8 pin 12F series. Keep in mind that the size of the PIC will be determined by what will be connected to the PIC. I used an external clock chip on projects I build because I can't risk losing the time and I also need to control daylight saving time automatically. I provide backup power with a coin battery so if the main power is lost, my clock is still running.

I strongly suggest that if you are new to PICs to spend some time reading thru the various posts here and study up.

There are alot of great people on this forum and even some good guru's that will help you out. Just remember they won't do something for you if you haven't shown some effort.

Have a nice day!

BobK

[oakkathebest]

Thank you for your suggestions but I would like to know is there any peculiar features in PIC 16 that force to make clock project. For example, during presentation if people ask me why do u use PIC16 instead of PIC 18, how shd I say? Moreover, it has been taught in the school. Please help me for this part. Thank you.

[BobK]

Hi OAk,

What do you want the PIC to do beside be a clock? Why you choose a specific PIC could be because you just happen to have one on hand, you've done other projects with this specific PIC because that's what you learned on. Most of the reading I did early on was based on the 16F84. It's pretty much a dead horse now being replaced by newer units with more memory and lower cost. Reading through these forums you will find people using 16F628A's, 16F877A, 18F452 or 18F2450's. It is up to you what you want to use based on your knowledge and project needs.

If someone asks you why did you use a 16F instead of an 18F you could just tell them you ran your finger over the page with your eyes closed and when you stopped moving your finger, it was on a 16F part number.

What kind of clock are you planning on building? Will you be using 7 segment displays or an LCD display? Will you be using a separate clock chip or will you be using the PIC to generate the clocking pulses and registers to keep track of the time? I really thought I covered this in my first reply.

Take some time and read through our forum. Get some ideas if you don't have any formulated yet.

HTH,

BobK

PS. You weren't on this forum last year as ENG444 were you?

[oakkathebest]

lol
Thank you for your reply and suggest. Nope, I was not here last year. I am doing a time and temperature talking devices specially for the blind using DS1307, DS1620, EMIC and PIC16 chips. I try to read first and ask you again My supervisor always asked me why I used PIC 16 instead of PIC 18. Last year in our school we were taught PIC 18. So, he asked me it would be easier if I use PIC 18. In fact I used PIC 16 because i saw lots of clock project uses PIC 16 in the internet.

[Jumper]

If I started to make a new project I would choose some of the more powerful PIC:s today. Of course they are a bit more expensive but they will give you much more possibilities when you find new things you want to do down the road. This will also help you to do the next project faster since you have already code and schematics that you can use to get started with.

If you plan to write all code in PBP it does not really matter if you go for 18 or 16 series.

I think PIC18F4550 (USB is always useful)

16F877A is also a good choice since you can, if you need more memory, drop in 18F452 or 18F4620 on the same footprint (they share the same pinout for the PT versions at lest)

I guess when your project is finished you will have a giant display, field upgrade using bootloader and many many more things you never planned to have from the beginning. So if it is not a matter of cost and availability I would say bigger is better.

But then your teacher will ask why you didnt choose a cheaper PIC for such a simple job... they will always ask this and that.

I would not choose a SMD package that has more then 44 pins. 44 pin packages are still possible to solder by hand.

If you dont have a need for serial communication and want to reduce cost I would choose a PIC with a built in oscillator.

[oakkathebest]

Timer can be used in sleep mode and will generate a wakeup interrupt on overflow. What does that mean? What does sleep mode mean? What is the advantage? Does PIC 18 also have this?