ADC broke when I switched from an ATmega16 to ATmega1284p

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fiebigc
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Posted by fiebigc: Thu. Mar 10, 2011 - 06:21 AM
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I ran out of memory and I switch the project I'm working on from an ATmega16 to an ATmega1284p. When I did my ADC broke.

Here are my functions using the ADC:

void initializeADC(void)
{
	ADCSRA |= (1 << ADPS1) | (1 << ADPS0);				// Set ADC prescalar to 8

	ADMUX |= (1 << REFS0);						// Set ADC reference to AVCC
	ADMUX |= (0 << ADLAR);						// Left adjust ADC

	ADMUX |= (1 << MUX2) | (1 << MUX1) | (1 << MUX0);	// Select ADC Channel 7

	ADCSRA |= (1 << ADEN);								// Enable ADC
}

unsigned int getAdcValue(void)
{
	ADCSRA |= (1 << ADSC);							// Start A2D Conversions 

	while(!(ADCSRA & (1<<ADIF)));					// Wait for conversion to complete

	return ADCL | (ADCH << 8);							// ADCL must be read first.
}

void disableADC(void)
{
	ADCSRA |= (0 << ADEN);								// Disable ADC
}

My ADC was working fine on the ATmega16. However now with the ATmega1284p I receive these compiler errors:

Build started 9.3.2011 at 22:00:51
avr-gcc.exe  -mmcu=atmega1284p -Wall -gdwarf-2 -std=gnu99 -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -MD -MP -MT AVR-ADC-functions.o -MF dep/AVR-ADC-functions.o.d  -c  ../AVR-ADC-functions.c
../AVR-ADC-functions.c: In function 'initializeADC':
../AVR-ADC-functions.c:6: error: 'ADCSRA' undeclared (first use in this function)
../AVR-ADC-functions.c:6: error: (Each undeclared identifier is reported only once
../AVR-ADC-functions.c:6: error: for each function it appears in.)
../AVR-ADC-functions.c:6: error: 'ADPS1' undeclared (first use in this function)
../AVR-ADC-functions.c:6: error: 'ADPS0' undeclared (first use in this function)
../AVR-ADC-functions.c:8: error: 'ADMUX' undeclared (first use in this function)
../AVR-ADC-functions.c:8: error: 'REFS0' undeclared (first use in this function)
../AVR-ADC-functions.c:9: error: 'ADLAR' undeclared (first use in this function)
../AVR-ADC-functions.c:18: error: 'MUX2' undeclared (first use in this function)
../AVR-ADC-functions.c:18: error: 'MUX1' undeclared (first use in this function)
../AVR-ADC-functions.c:18: error: 'MUX0' undeclared (first use in this function)
../AVR-ADC-functions.c:20: error: 'ADEN' undeclared (first use in this function)
../AVR-ADC-functions.c: In function 'getAdcValue':
../AVR-ADC-functions.c:25: error: 'ADCSRA' undeclared (first use in this function)
../AVR-ADC-functions.c:25: error: 'ADSC' undeclared (first use in this function)
../AVR-ADC-functions.c:27: error: 'ADIF' undeclared (first use in this function)
../AVR-ADC-functions.c:31: error: 'ADCW' undeclared (first use in this function)
../AVR-ADC-functions.c: In function 'disableADC':
../AVR-ADC-functions.c:36: error: 'ADCSRA' undeclared (first use in this function)
../AVR-ADC-functions.c:36: error: 'ADEN' undeclared (first use in this function)
make: *** [AVR-ADC-functions.o] Error 1
Build failed with 18 errors and 0 warnings...

I don't understand why these registers are unknown. They are clearly stated on page 258 of the datasheet.

Does anyone know why this broke?

Thanks.

AVR Studio 4.14.589
GCC Compiler
Windows 2000

Tags:

AVR Microcontrollers, megaAVR and tinyAVR, ATmega128, ATmega1284, ATmega16
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Bronze Markbobgardner
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Posted by bobgardner: Thu. Mar 10, 2011 - 03:11 PM
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You should wait for conversion complete on the ADSC flag to go low. ADIF is used with interrupts, must be cleared

Imagecraft compiler user

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Koshchi
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Posted by Koshchi: Thu. Mar 10, 2011 - 04:34 PM
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Your code compiles fine for me (when I add a 'main' into the mix. Are you sure that you have included ? If I comment that out I get pretty much what you got.

Regards,
Steve A.

The Board helps those that help themselves.

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dksmall
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Posted by dksmall: Thu. Mar 10, 2011 - 04:40 PM
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Dumb question but you did change your device setting in Studio to the 1284, right?

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fiebigc
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Posted by fiebigc: Thu. Mar 10, 2011 - 07:21 PM
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Thanks for your replies.

@bobgardner

I thought that's what this line did:

while(!(ADCSRA & (1<<ADIF)));

@Koshchi

I do indeed include . I have a lot of other stuff that is dependent on this library and I am not receiving compiler errors for those.

@dksmall

Yes, I did change the device settings. After changing the device specification is when I began to receive the compiler errors for registers that have different names between the two devices.

There were a number of registers that I had to update, like the Timers, when I switched devices. Only after I corrected the register names for the timers did the compiler throw errors about my ADC registers. The compiler wasn't complaining about my ADC registers when my timer registers were wrong.

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Bronze Marktheusch
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Posted by theusch: Thu. Mar 10, 2011 - 07:33 PM
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Why don't you make a small complete test program, and post it in its entirety? Probably the makefile, too? The GCC people will have to comment on that.

And also GCC people--is there a way with intermediate files, pre-processor output, and the like to see the actual contents that io.h pulls in?

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Koshchi
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Posted by Koshchi: Thu. Mar 10, 2011 - 08:20 PM
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Quote:
I thought that's what this line did:
while(!(ADCSRA & (1<<ADIF)));

No, that line checks to see if it is high. To clear the bit you need:

ADCSRA |= 1<<ADIF;
   ADCSRA |= (0 << ADEN);                        // Disable ADC

This line does nothing. You need:
ADCSRA &= ~(1<<ADEN);

   return ADCL | (ADCH << 8);                     // ADCL must be read first.

But this line of code does not guarantee that ADCL is read first. Just use:

return ADCW;

Quote:
I do indeed include .
But do you do it in the file that these functions exist in?

Regards,
Steve A.

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