Return value to Register

How do you return a value back to the register. I have 2 functions, one reads the value of the register

Code:

---

#define IOBASE 0x4000

void leesRegister( unsigned char* Register )
{
  Register[0] = *( ( unsigned char* ) ( IOBASE + 0x10 ) );
  Register[2] = *( ( unsigned char* ) ( IOBASE + 0x12 ) );
  Register[4] = *( ( unsigned char* ) ( IOBASE + 0x14 ) );
}

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and the other must return the value of ddr back to the register

Code:

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void schrijfRegister( Register, ddr )
{
}

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But what keywords do I have to use etc? just a little help can get me started.

Microcontroller = Fujitsu
Datasheet = MB90F4 http://www.datasheets.org.uk/preview/2236300.html

No keywords[1] involved here, but perhaps you want to think about how you would do the exact opposite of what your leesRegister does.

[1] keywords in C are the words defined by the compiler, such as "if", "while", etc.

--
Mats

How does a code, that does the exact opposite, look like?

Code:

---

#define IOBASE 0x4000

void schrijfRegister( unsigned char* ddr )
{
  ddr[0] = *( ( unsigned char* ) ( IOBASE + 0x10 ) );
  ddr[2] = *( ( unsigned char* ) ( IOBASE + 0x12 ) ); 
  ddr[4] = *( ( unsigned char* ) ( IOBASE + 0x14 ) );
}

---

is this correct?

Quote:

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Originally Posted by Lettin03

How does a code, that does the exact opposite, look like?

Code:

---

#define IOBASE 0x4000

void schrijfRegister( unsigned char* ddr )
{
  ddr[0] = *( ( unsigned char* ) ( IOBASE + 0x10 ) );
  ddr[2] = *( ( unsigned char* ) ( IOBASE + 0x12 ) ); 
  ddr[4] = *( ( unsigned char* ) ( IOBASE + 0x14 ) );
}

---

is this correct?

---

No, that's EXACTLY THE SAME, not the OPPOSITE.

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Mats

Could you show how the opposite looks like then? I cant figure it out and it's driving me crazy

Quote:

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Originally Posted by Lettin03

Could you show how the opposite looks like then? I cant figure it out and it's driving me crazy

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Give it a try - think about what you want to do. Your first function reads FROM a register, the new function should do what?

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Mats

Uhm I'm thinking about the same code, but = means the variable becomes. Should I use ==?

Quote:

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Originally Posted by Lettin03

Uhm I'm thinking about the same code, but = means the variable becomes. Should I use ==?

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So what do you actually say that this function should do: describe what it does in words, and I think it will be clear to you what you need to do and how to write the code!

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Mats

The code has to return the ddr value back to the register

Code:

---

#define IOBASE 0x4000

void schrijfRegister( Register, unsigned char* ddr )
{
  (IOBASE + 0x10) = Register[0], unsigned char*;
}

---

Is this more like it?

You've got the rigth idea, but you seem a little confused about which part of the components belong together.

--
Mats

I Think I have written the right code, but there seems to be an error

Code:

---

void schrijfRegister( int Register, unsigned char ddr )
{
  ( IOBASE + 0x10 ) = ( int ) ( unsigned char );
}

---

Can you see what I am doing wrong?

matsp, judge my code above

If I were to ask you to do "a[i] = y" backwards, what would you do?

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Mats

"a[i] = y" backwards would be "y[i] = a" I think. But my code isn't suppost to be the exact opposite cause is contains 2 arguments in stead of 1. Maybe the code must be like this

Code:

---

void schrijfRegister( int Register, unsigned char ddr )
{
  ( int ( IOBASE + 0x10 ) ) = unsigned char;
}

---

But there still is an errpr

Code:

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E4062C: syntax error near `0x4000'

---

Quote:

---

Originally Posted by Lettin03

"a[i] = y" backwards would be "y[i] = a" I think. But my code isn't suppost to be the exact opposite cause is contains 2 arguments in stead of 1.

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If a is an array, and y is a simple variable, your backwards version wouldn't compile, right?

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Mats

That's right, I suppose [I]"a = y" will become "y[a] = i" then? I don't see any toher options. So the code

Code:

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Register[0] = *( ( unsigned char* ) ( IOBASE + 0x10 ) );

---

Backwards will be

Code:

---

( int ( IOBASE + 0x10 ) ) = unsigned char;

---

Or not?

I'm sorry to have to say this, but I think you need to read chapters 1, 2 and 3 or so of your C programming book - you are currently trying to swim in the deep end, and you can't even swim in the shallow end with floating aids.

--
Mats

Thank you for your compliment, you are right though. This code will be my first code ever written in program languace. Actually yesterday I kept trying to find the right code. I believe this is it

Code:

---

*( (unsigned char*)( IOBASE + 0x10 ) ) = ddr;

---

Thank you for being critic on my work. It get's the best out of me

Now we're going somewhere. Is that working right for you?

--
Mats

Code:

---

*( (unsigned char*)( IOBASE + 0x10 ) ) = ddr;

---

This is not what I would term 'Beginner's material.' Perhaps you might want to start with the fundamentals of pointers and such before you try to tackle something like this. Even to fairly experienced programmers this line of code is quite ugly.

Quote:

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Originally Posted by Bubba

Code:

---

*( (unsigned char*)( IOBASE + 0x10 ) ) = ddr;

---

This is not what I would term 'Beginner's material.' Perhaps you might want to start with the fundamentals of pointers and such before you try to tackle something like this. Even to fairly experienced programmers this line of code is quite ugly.

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I agree - this is NOT beginner C, which is why I suggested to the OP to re-read the first few chapters in the C book.

Yes, if you read back to my original proposal, I was actually intending to hide all those casts inside a macro [at least, that way, the code looks a bit tidier]. For some reason or another the OP decided to not follow that pattern.

--
Mats