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ARM LPC2000 GPIO problem

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T

Tamasco

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I have a problem reading input pins on the LPC2138.
I used the following assignment in the Keil uVision3 and got the following
error:
CODE
unsigned int Key_0=IOPIN1& 0x00080000 ; // Read input pin P1.24

ERROR
error: KeyPad.c(36): error: #28: expression must have a constant value.

What could be the problem?
 

Hello,

It is possible that you are trying to Do a C++ thing in C. You should do it the C way:
CODE
unsigned int Key_0;
int Key_0=IOPIN1& 0x00080000 ; // Read input pin P1.24

You cant arbitrary load defined vars in C.
Best of Luck!!
 

    T

    Tamasco

    Points: 2
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Hi

Use long insted of unsigned int, IOPIN is 32bit wide register

All the best

Bobi
 

    T

    Tamasco

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@ boseji and bobcat1

thanks bros. I'll do that and give u the feedback.
 

hi
u might not need long as uv3 allocates 32 bit for a int,if ur using arm mode.
Shakeel
 

    T

    Tamasco

    Points: 2
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Thank you all for your input. I think the problem is not a simple one. I tried all the above suggestions but I still can't figure out why the error keeps on showing.
I guess there must be a special way to read an input and store the value.
 

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