AVR-Chat

- 'temp' seems to be used inside and outside the INT routine.
- The INT return address are pushed forever...

    MJ


Loren Boyle wrote:
> There is a problem in the interrupt service routine  Timer2_Ovf:  The last
> part of the code is:
>
> hh:
>  ldi Temp,LOW(Sec1) ; After interupt completed go back to Sec1
>  push Temp
>  ldi Temp,HIGH(Sec1)
>  push Temp
>  reti
>
> Two bytes are pushed onto the stack and then a rti is executed.  The return
> is to the address formed by the two pushed bytes and not the actual return
> address which was pushed onto the stack at the time of the interrupt.
>
> Loren
>
> Email: Loren_Boyle@bcit.ca
>
>
>
>
>                                                                                                                                                  
>   From:       STEVEN HOLDER <s.holder123@btinternet.com>                                                                                         
>                                                                                                                                                  
>   To:         AVR-Chat@yahoogroups.com                                                                                                           
>                                                                                                                                                  
>   Date:       29/04/2009 01:29 PM                                                                                                                
>                                                                                                                                                  
>   Subject:    Re: [AVR-Chat] Sleep ATMega16                                                                                                      
>                                                                                                                                                  
>   Sent by:    AVR-Chat@yahoogroups.com                                                                                                           
>                                                                                                                                                  
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>
>
> Try reintialising the uart when you wake up, turn it off when you go to
> sleep. Set the pins as input high impedance in sleep mode.
>
> It is a good idea to have a sleep routine run just before you go to sleep,
> then a wake routine, so that any values can be set/ cleared consistantly.
>
> Regards
>
>
> --- On Wed, 29/4/09, Gmail <moatazhussein@gmail.com> wrote:
>
>
> From: Gmail <moatazhussein@gmail.com>
> Subject: Re: [AVR-Chat] Sleep ATMega16
> To: AVR-Chat@yahoogroups.com
> Date: Wednesday, 29 April, 2009, 8:55 PM
>
>
>
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>
>
> What i did is that when it wakes, i inserted a delay of 200 ms then started
> to get data from AD (SPI) and send it (UART), nothing happened; same
> results.
>
> Moataz Hussein
>
> ----- Original Message -----
> From: wagnerj@proaxis. com
> To: AVR-Chat@yahoogroup s.com
> Sent: Wednesday, April 29, 2009 9:53 PM
> Subject: Re: [AVR-Chat] Sleep ATMega16
>
> Be aware that the processor takes time to wake up. Also, be careful NOT to
> sleep until all of the bytes have been sent. This means staying awake
> until the very last stop bit has left the UART. In other words, you cannot
> just put a byte into the UDR, then sleep. You need to wait until the byte
> is actually finished.
>
> Jim Wagner
> Oregon Research Electronics
>
>   
>> I am working on on a system to record temperature on a flash memory at a
>> programmed rate.
>> As there is nothing to be done between samples (1 Sec- 15 Mins) and it is
>> battery powered I want it to sleep between samples.
>>
>> I am using Mega 16, A/D MCP3550 on Spi, running on 3.6864 Mhz Crystal.
>>
>> The first step I did was to read from A/d and send it by uart to check
>> readings, it was ok.
>>
>> When I started to introduce sleep, I got zeros received by uart! even the
>> number of bytes sent.
>> So I conclude that the problem is when waking after the sleep, is there
>> any thing that I missed or settings to be done so that I get it work as I
>> want it?
>>
>> Code Bellow.
>>
>> Thanks,
>> Moataz Hussein
>>
>> ;/////////// //////
>> ; Timer2 overflow
>> ;/////////// //////
>>
>> Timer2_Ovf:
>>
>> clr temp ; Disable sleep
>> out mcucr,temp
>>
>> dec temp1 ; Loops counter
>> brne hh
>>
>> ldi temp1, 225 ; Reset Counter value to 225 when done
>>
>> hh:
>> ldi Temp,LOW(Sec1) ; After interupt completed go back to Sec1
>> push Temp
>> ldi Temp,HIGH(Sec1)
>> push Temp
>> reti
>>
>> ;/////////// //////
>> ; Main
>> ;/////////// //////
>>
>> Main_sample:
>>
>> rcall sample ; Read from A/d And send by UART
>>
>> sei
>> ldi temp, 0b01000000
>> out timsk, temp
>>
>> Ldi Temp, 0b00000100 ; Prescaller 64
>> out tccr2, temp
>> ldi temp1, 225 ; No of loops to get 1 Sec
>>
>>
>>
>> TMRLOOP:
>>
>> ldi temp,0b01010000 ; Enable sleep, mode
>> ; out mcucr,temp
>> sleep
>> Rjmp TMRloop
>>
>> Sec1:
>> Ldi temp, 225
>> cpse temp, temp1
>> rjmp tmrloop
>>
>> Rjmp Main_sample
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>     
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