data sheets are nothing for ccs c programmer.

ron · Guest

Hi

I am a programmer for 1 year now in ccs c, and today I understood that I just can't work on my own and need to copy codes all the time.
That's because data sheets are for assembler programmers !

For example, if I want to learn one of my pic's protocols, the data sheet will mean nothing to me because its all about sets registers and written for assembler programmers. Nothing will help for c programmer. Nothing.

I don't want registers! I want exactly syntax to all function I write.
And that's why I can't work on my own and need to copy code from the net every time I need something new. I hate that ! And its not just me! People don't look too much on data sheets because setting registers don't help for c programmer. And the controller scheme doesn't help to programing.

The help of CCS c is really nothing. Because I can't read help about a subject and get it into a code. Its a general help not specific syntax!
I am engineer, and not just stupid kid. But I just can't take this help into a code. Its so unclear.

So my question is, where can I find a real guide, that when I need to write for a eeprom or write rs232 I can find the exact code with exact explanation. Not just a general talking ! I need a real source to program!

From where you people take your syntax to do something new ?????

Thanks a lot (all my knowledge is from here anyway).

eskimobob · Joined: 07 Feb 2009 Posts: 40

Probably the best thing to do is find one of the CCS examples that has something relating to what you need to do then examine it and figure out how it works. Cool

FvM · Joined: 27 Aug 2008 Posts: 2337 Location: Germany

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

What is the problem with setting and reading registers with C? With any other uP C compiler you have to do that all the time. CCS spares you sometimes, but can't always.
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PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Post one example (a short one) about one module, such as ADC or PWM,
etc. Explain how you're lost. Then we'll tell you how we do it.

ron · Guest

Thanks for responds.

For example- I know how to do a pwm, and did it so many times in a complex systems, but, don't really understand what exactly the timer is doing. How can I do that with another timer, for example- the formula to a pwm ! The only way to know that is go here and ask!
It's not appear anywhere !

Another example: I need now to operate 4 channels pwm. How ??? where??

This information is missing. Without you I didn't have a job now !

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Are you talking about hardware PWM ? The formula for the PWM
frequency is in every PIC data sheet (that has a CCP module).

Mostly, if you don't know the answer, you have to learn how to use
Google to search for the information. Microchip has a large number
of tutorials and application notes available. Use Google to search it.
Example of a Google search string:

Douglas Kennedy · Joined: 07 Sep 2003 Posts: 755 Location: Florida

Well in this universe you can't learn just one way of doing things then expect it to give you access to solutions in every conceivable circumstance. PIC devices are by design focused on hardware. Yes they aren't even soldered to a PCB when most of us see them for the first time. The pins are specific
MCLR needs to be tied high and A0 is often open drain certain pins are assigned to receive the crystal oscillations etc. Knowing C visual basic or whatever isn't enough on a PC you still have to find the hardware on/off button. Now the PIC requires a bit more curiosity what with registers fuses and interfaces like I2C rs232 SPI PWM and so on but that's what makes the devices useful.

Wayne_ · Joined: 10 Oct 2007 Posts: 681

FvM and PCM Programmer are completely correct.

I use datasheets ALL the time and if you are doing embedded programming whether in Assembler, C or any other language you had better learn to read and understand them.

You will eventually try to drive a chip in your hardware that you cannot find a library for, sure people will help you develop one on forums like this but if you come here and ask someone else to read the datasheet then write the software for you you will find that the help starts to disappear.

I currently use CCS for PIC C but I also am working with Embedded Windows CE hardware writing code in C#, .net but I have had to resort to reading the datasheet and writing code in C (dlls) to control the hardware. The other option is of cause to pay the developers of that hardware to write it for me, but then why am I being paid ?

And before anyone else says it, .net for embedded programming, yes I know, this is why I have had to resort to C for some stuff.

Guest · Posted: Mon Nov 09, 2009 1:24 pm

You can't do embedded C programing unless you're intimately familiar with the chip you're using. That means familiarity with all the chips register, I/O's, timers etc. That in turn means also being a software as well as a hardware engineer.

While C is higher up than assembly one has to know the nuts and bolts of the chip. That's why it's usually much easier for assembly programmers to go into C than the other way around.

Formula for doing it:
Learn C
Learn the chip's specs
See how others have solved similar problems in this forum.

If you don't follow these simple (but time consuming) steps it will come back and haunt you.

Cheers

FvM · Joined: 27 Aug 2008 Posts: 2337 Location: Germany

You also may wonder, why CCS C has an option to install all PIC datasheets with the compiler? Obviously they don't think, that the compiler manual is a sufficient work basis.

Anyway, I understand some of Ron's thoughts. A problem e.g. with the PWM manual chapter is, that it's implicitely talking of PIC hardware details (e.g. 8/10 bit resolution for duty cycles) without naming them. If you're not familiar with this hardware details, you'll need some time to acquire what's omitted here.

You can imagine e.g. an overview, which built-in function is actually valid for a particular PIC. Reading the manual, it's not obvious, why set_pwm5_duty() is not working with your chip...

bkamen · Posted: Mon Nov 09, 2009 10:05 pm

I have to agree with the sentiment that this isn't Window or Linux or insert_big_os_with_lots_of_abstration_to_hard_here.

This is a microcontroller. You are the king of the OS it runs (if you can even call it an OS.. so to speak).

So it's really a different ball game. I have worked with lots of talented programmers in the past that know absolutely zilch about hardware.

They are fantastic programmers, but they don't know hardware. They are not firmware programmers.

It's really 2 different worlds. Learn to love your datasheets.

-Ben
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eskachig · Joined: 27 Mar 2009 Posts: 8

Guest · Posted: Tue Dec 01, 2009 5:00 pm

Hi,

Why not use snippets of the Microchip asm examples as is?
One of the reasons I chose CCS was the excellent & simple use of in-line assembly.

Some final words of comfort;
We are lucky, lucky guys, considering the huge amount of PIC & C-examples available!

I'm also working with GSM-hardware that's very nice, but has appalling documentation and "examples" that leave you slightly dizzy for 45 minutes.. Think "manual for chinese DVD-player translated to Norwegian and back again".. Smile

We are lucky, lucky guys!

/BdeB

rnielsen · Joined: 23 Sep 2003 Posts: 852 Location: Utah

I rely _heavily_ on data sheets whenever I'm doing a project. Virtually every component will have some sort of data sheet. Some are better than others but I use them a lot, especially for PICs. You need to know what 'hardware' is inside first before you can control it properly.

For example, using a timer. Some timers have a pre-scaler and a post-scaler. Some just have one scaler and not both. Some timers are 8-bit and others are 16-bit. I/O pins have multiple uses and, depending on how you set things up, different hardware will be enabled/disabled.

There might be a lot of ASM examples given in the data sheet. I'm not an ASM programmer. I've never known how to program in assembly and, quite frankly, I don't want to learn. Registers are wonderful! They let you have direct access to the 'guts' of the PIC. It's not hard to monitor/manipulate them and can come in handy. Take the i2c_isr_state() command used in a slave. Instead of using that command I monitor the register, directly, instead.

Don't be intimidated by the PIC. I've used various code that has been posted here. We're able to access registers for a reason, because they can aide in controling/monitoring what's happening inside.

Experiment!!!

Ronald