[Icc-avr] Interrupt Help Please (Happy New Year)

Thu Jan 3 09:57:29 PST 2008

Hi Andy,

latest errata (datasheet rev C) tell of "high current consumption in sleep mode". Maybe this is one of reasons for your sleep current problem.

Best regards,
Johannes

> Hi john,

> I am actually powering the RTC from a port as it only takes 100uA ( not my
> desgin, more a temparay fix).

> The thing is the code works with out change alsong as i dont't plug in the
> USB. So i can make it sleep and resume from sleep all day long by swaping
> the power over from backup battery to power (so PORTD BIT 1 goes high and
> low). but if i plug in the USB connector and disconnect the USB connecor to
> make the processor sleep. the sleep current goes p to 112 - 120uA.

> Can you see something in the USB that i am not turnning off, it seems to me
> that the USB or some part of it is staying on.

> Andy

> ----- Original Message -----
> From: "John Baraclough" <j_baraclough at zetnet.co.uk>
> To: "Discussion list for ICCAVR and ICCtiny Users. You do NOT need
> tosubscribe to icc-announce if you are a member of this."
> <icc-avr at imagecraft.com>
> Sent: Thursday, January 03, 2008 3:37 PM
> Subject: Re: [Icc-avr] Interrupt Help Please (Happy New Year)

>> The processor is clearly in a different state when it goes to sleep from
>> when it first starts up. At a guess, I would say you are leaving a port
>> pin enabled and driving a low level out to a pull-up resistor (possibly
>> more than one). Calculating the extra current; 112uA would be the current
>> drawn through a 47k resistor from a 5V supply (or 30k and 3.3V).
>>
>> What is the mechanism for turning off the RTC? The ideal way to do this is
>> to use a resistive pull-up/pull-down to turn off the RTC and then
>> overdrive it with the appropriate level from a port pin to turn it on.
>> When the processor goes to sleep just tri-state all the port pins so there
>> is no current drawn.
>>
>> HTH
>>
>> John
>>
>> Andrew wrote:
>>> Hi john/anybody ,
>>>  I have a intresting/anoying problem. to recap. I have an AT90USB162. i
>>> am basically trying to send the processor to sleep if Bit 1 on PORTD is
>>> high and wake when the PIN goes low. The basically tells the processor it
>>> has lost main power and is now running on a battery.
>>>  I have the code working well and i am getting 7.12uA when the Processor
>>> is asleep.and my pin interrupt routine works and wakes the processor if
>>> PORTD BIT1 is low and returns back to the 7.12uA when PORTD BIT1 is high.
>>> The problem i have is when i pug the USB in. This also has the same
>>> effect on PORTD BIT 1 as it now takes over powring the system from the
>>> battery.
>>>  So as before if the USB connector is pugged in PORDT BIT 1 goes low and
>>> the processor resumes from sleep. this also works and i can use the USB
>>> port as a serial emulator using some atmel exmaple code. The probelm
>>> comes when i unplug the USB connector. Which sends PORTD BIT 1 high and
>>> thus the processor goes to sleep but it only goes down to 119uA not the
>>> 7.12uA i was getting before. I have checked and the processor is asleep
>>> as the external oscillator is turnned off. So some part of the USB must
>>> be still enabled. Can anybody suggest a solution: -
>>>  CODE
>>>  NOTE : -
>>>
>>> #define USB_CONNECTED (PIND & 0x01)
>>> #define BAT_CONNECTED (PIND & 0x02)
>>>
>>> are defined in a sepearte c file.
>>>
>>>  * *
>>>
>>> *void* sleep(*void*);
>>> *void* wake(*void*);
>>>
>>> //-----------------------------------------------------------------------------
>>> //
>>> // Function name : Sleep
>>> //
>>> // Returns : None
>>> //
>>> // Parameters : None
>>> //
>>> // Purpose : Send the processor into sleep mode (Low power)
>>> //
>>> //-----------------------------------------------------------------------------
>>> *void* sleep(*void*)
>>> {
>>>
>>> SPCR = 0x00;                    // Power Down the SPI
>>> UCSRB = 0x00;                // NOT FOUND THIS IN THe DATASHEET
>>>
>>> REGCR = 0x01;                 // Disable the USB Regulator
>>> RTC_POWER_OFF          // Turn the Power too the RTC OFF (PORTD4)
>>>
>>> EICRA = 0x08;                // Change INT1 Pin Interrupt to Falling Edge
>>> (INT1)
>>>
>>> PRR1 = 0x81;                    // Turn Off the USB and USART using the
>>> power reduction register
>>>
>>> SMCR = 0;                         // Clear SMCR Register
>>> SMCR = 0x05;                   // Configure Sleep Register for Deep Sleep
>>> asm(/"sleep"/);                     // Put Processor into Deep Sleep
>>>
>>> }
>>>
>>> //-----------------------------------------------------------------------------
>>> //
>>> // Function name : Wake
>>> //
>>> // Returns :
>>> //
>>> // Parameters :
>>> //
>>> // Purpose : Return from Sleep mode and restart devices
>>> //
>>> //-----------------------------------------------------------------------------
>>> *void* wake (*void*)
>>> {
>>> PRR1 = 0x00;                 // Restart the USB from Power Reduction Mode
>>> EICRA = 0x0C;              // Change the Battery on pin to interrupt on
>>> rising edge (INT1)
>>> RTC_POWER_ON        // Turn the RTC Power Supply back on (PORTD4)
>>>
>>> UCSRB = 0x98;               // HAVE NO IDEA WHAT THIS REGISTRY IS FOR
>>> SPCR = 0x5C;                 // Restart the SPI
>>> Usb_enable_regulator();    // Enable the USB regulator
>>> }
>>>
>>> //-----------------------------------------------------------------------------
>>> // Main Program Loop
>>> //-----------------------------------------------------------------------------
>>> *void* main(*void*)
>>> {
>>> init_devices();                 // Initilise all the devices
>>>
>>> Usb_enable_regulator(); // Enable the USB Regulator
>>> usb_scheduler_init();       // Set up the USB Scheduler
>>>
>>> *while* (1)
>>> {
>>>
>>> *if*(USB_CONNECTED) // If the USB Connected Pin is High
>>> {
>>> usb_scheduler_tasks();    // Schedule the USB tasks
>>> }
>>>
>>> *if*(BAT_CONNECTED)  // If the Battery Connected Pin is high
>>> {
>>> sleep(); // Call the Sleep function
>>> NOP(); // Small Delay
>>> NOP(); // Small Delay
>>> wake(); // Wake from Sleep and restart USB and SPI
>>>
>>> }
>>>
>>> }
>>> }
>>>
>>>  Andy
>>> ------------------------------------------------------------------------
>>>
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>>>
>>
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