calculate average

Log in or register to post comments
Go To Last Post
6 posts / 0 new
Author
Message
padewinter
padewinter's picture
Level: Rookie
Joined: Wed. Mar 3, 2010
Posts: 36 View posts
Location: Netherlands
#1
Posted by padewinter: Thu. Mar 12, 2015 - 02:21 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi all,

 

I calculate the average of 16 number with the following code in a attiny24A. This code works fine in a atmega328.

The input voltage is constant so the average must be constant too, but the average drops to zero and I can't find out why.

 

I take a new sample (from a steady voltage) everytime the interrupt is executed. Than I just put SumV1 (the average value) to a PWM output. This goes to zero.

 

I don't think I use anything that is not possible inside the attiny24A.

Hopefully somebody can give me a clue.

Greetings, Patrick

 

Attachment(s): 

Binary Data Average.asm

Tags:

AVR Microcontrollers, megaAVR and tinyAVR
Top
ki0bk
ki0bk's picture
Level: Raving Lunatic
Joined: Mon. Sep 8, 2014
Posts: 8404 View posts
Location: Olathe KS
Posted by ki0bk: Thu. Mar 12, 2015 - 03:00 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

It would help if you posted a complete small program that demos the problem.   Can you run it the simulator and duplicate your problem? 

One more question, are interrupts enabled anywhere in your program, if so, how have you protected the data registers used by your ave() function?

 

Jim

 

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 101086 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
Posted by clawson: Thu. Mar 12, 2015 - 03:03 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

That's half a program. It mentions variables and labels that are not shown.

Top
padewinter
padewinter's picture
Level: Rookie
Joined: Wed. Mar 3, 2010
Posts: 36 View posts
Location: Netherlands
Posted by padewinter: Thu. Mar 12, 2015 - 03:07 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I will make a total program and will comeback on this issue.

 

Top
Koshchi
Koshchi's picture
Level: 10k+ Postman
Joined: Wed. Nov 17, 2004
Posts: 15658 View posts
Location: Vancouver, BC
Posted by Koshchi: Thu. Mar 12, 2015 - 04:46 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0
		ldi		ZH,high(Voltmes1)	;Set the pointer at the start of the averaging table 
		ldi		ZL,low(Voltmes1)

Should that not be (Voltmes1<<1) to make it a byte address?

Regards,
Steve A.

The Board helps those that help themselves.

Top
skeeve
skeeve's picture
Level: Raving Lunatic
Joined: Sun. Oct 29, 2006
Posts: 5392 View posts
Posted by skeeve: Thu. Mar 12, 2015 - 04:56 PM (Reply to #5)
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Koshchi wrote:

		ldi		ZH,high(Voltmes1)	;Set the pointer at the start of the averaging table 
		ldi		ZL,low(Voltmes1)

Should that not be (Voltmes1<<1) to make it a byte address?

No.  SRAM addresses are byte addresses.

The byte/word problem comes from flash addresses in which gnu believes in bytes and the processor believes in words.

In such cases one should >>1 or gs .

Iluvatar is the better part of Valar.

Top