Processor Companion with Alarm Function to wake up Main Computer

[edlee]

I have been looking for a replacement for my HP 200LX palmtop computer.  Although the HP 200LX is not fast by modern standards, the HP 200LX can sleep for a month on a pair of AA batteries and then wake itself up to sound an appointment alarm or execute a program at a designated date and time.  For example, I have one of my HP 200LX computers set up to turn on the living room television, turn on the separate HDTV tuner, and change the channel to one of my favorite television shows once each week by running a program that sends infrared signals from the HP 200LX to the television set and the HDTV tuner.  I have another HP 200LX set up to back up its main memory contents to a compact flash card early each morning and charge the batteries if they need charging.

It would be useful to have a long standby alarm capability in a modern palmtop computer.  To maximize battery life, the computer would be completely shut down except for a processor companion.  The processor companion would have a real-time clock and nonvolatile memory to store the date and time of the next alarm.  At the appointed time, the processor companion would power on the main computer, and the main processor could run a calendar / appointment program or some other program, sound an alarm jingle, display a text reminder associated with the alarm, and load the nonvolatile memory of the processor companion with the next alarm date and time.  Such a palmtop computer could have more intelligence than typical alarm clocks by sounding wake-up alarms only on work days and not the weekends, for example.  If a person is traveling, then the person might not have easy access to a compatible electrical outlet in a foreign country or out in a field and might need to conserve battery life by shutting down the palmtop computer rather than putting it in standby or sleep mode.

Ramtron produced processor companions with a real-time clock and nonvolatile FRAM memory:

http://www.youtube.com/watch?v=vqja6qSvwyw

Cypress Semiconductor later acquired Ramtron.  A PDF file with information about one of their processor companion products is available at:

http://www.cypress.com/?rID=73539

While I do not know if the existing processor companions can do what I envision, it is an interesting possibility to consider.

 

[_wb_]

The standby time of the P1 is already about 1 week (lid closed, everything idle or off). I hope that the P2 gets a SoC and RAM that consume even less power when inactive, so the standby time with wifi on would be a week, and with wifi off maybe 2 or 3 weeks. I don't know how realistic that hope is.

 

[WizardStan]

The Pandora also already has a wake up alarm built into the hardware clock, and the Pandora can look at an interrupt to know whether it was powered on via switch, battery, AC plug, or alarm; all that's missing is software to control it the way you want.

The P2 will almost certain be able to do the same, and by then it may even have a suspend to disk feature which will give you the months of down time you want (as opposed to the days/week we currently get with suspend to RAM)

 

[Asiyura]

The problem is that pandora's clock tend to be messed up quite easily…

When coming back from low-powered mode, I frequently have a date/time that is completely wrong

EDIT : For example, just picked it up and I get 14:43 (wow, almost right!) 30th november 2013 (nevermind…)

 

[WizardStan]

Have you run an update recently? Notaz put in a fix to properly reload the system clock from the hardware clock when coming out of sleep. That solves the problem except in the few cases where the system is reset while sleeping.

 

[Asiyura]

Have you run an update recently?

I keep my pandora up-to-date.

I guess my problem comes from the fact that sometimes, I get my battery completely drained (I tend to use the pandora as a phone charger when I'm away or to forget it running a game before getting to bed).

I've been toying with the idea of a small "daughterboard" with a button cell and a low power µcontroller that is accurate enough to work as RTC (and manage other thing like sensors and small vibration motor ). That way, even after power loss, the pandora would be able to "poke" the RTC µC and get a more accurate date/time even without internet connection.

 

[WizardStan]

No need to go that far. The TWL has a "backup battery" option. I'm not exactly certain which pins they are, but if you can find the the space for it just solder a button battery to those pins and the clock'll never stop.

Sensors are probably best connected to the existing i2c pads, and the KP-BL pads have been used for vibration. No need for extra micro controllers.

 

[Asiyura]

The micro controller would be to keep the KP-BL pads free (as people actually use them to install leds to illuminate the keyboard ).

I would indeed use the I²C pads to have the µC communicate with pandora.

It would be great to find those backup battery pads, but it'll have to wait for me to get some money back and buy a new pandora case (or a second pandora).

 

[mclien]

No need to go that far. The TWL has a "backup battery" option. I'm not exactly certain which pins they are, but if you can find the the space for it just solder a button battery to those pins and the clock'll never stop.

That would be indeed a cool hack.

@Kodeln:

the parts of the case are 1-3 EUR per part in the dragonboxshop....

 

[Asiyura]

No need to go that far. The TWL has a "backup battery" option. I'm not exactly certain which pins they are, but if you can find the the space for it just solder a button battery to those pins and the clock'll never stop.

That would be indeed a cool hack.

@Kodeln:

the parts of the case are 1-3 EUR per part in the dragonboxshop....

I don't even have that amount on my bank account right now…

EDIT : nothing bad, we just bought a new bed (previous one was really shitty and small)

 

[Exophase]

Are you sure you want to use a several hundred dollar device like Pandora for a task like this? You could probably rig up the same functionality using something far cheaper..

 

[edlee]

Having the functionality that I described in another device would require carrying a second device.  I would run out of pockets to carry things.  Carrying a second device would be less convenient than carrying just one device.

Do I understand correctly from WizardStan's previous post that the OpenPandora already has the capability to power on at a designated date and time?  It would be nice if the wake up time were mapped to a file.  A program could then simply write the time to the file to set the alarm to turn on the power if it is not already powered at that time.

An appointment program does not have to check how the computer was turned on.  The appointment program simply needs to know if it is the appropriate time to trigger an alarm that has not already been triggered.

 

[Exophase]

Having the functionality that I described in another device would require carrying a second device.  I would run out of pockets to carry things.  Carrying a second device would be less convenient than carrying just one device.

So I guess you're not looking for something to replace the device you use to turn on your TV since that won't work from your pocket. I expected you wanted to have that there all the time, since constantly putting it back where it can turn the TV sounds like more of a hassle than turning the TV on at the right time. What alarm functions do you want for a thing you can keep in your pocket but turned off for long periods of time?

Do I understand correctly from WizardStan's previous post that the OpenPandora already has the capability to power on at a designated date and time?  It would be nice if the wake up time were mapped to a file.  A program could then simply write the time to the file to set the alarm to turn on the power if it is not already powered at that time.

An appointment program does not have to check how the computer was turned on.  The appointment program simply needs to know if it is the appropriate time to trigger an alarm that has not already been triggered.

The hardware should be capable of doing, but I doubt that there's software to do this. You'd need to shutdown everything but the RTC. It does assume that there's an RTC output from the SoC that is properly wired to some wakeup on the PMIC.

 

[edlee]

I don't expect to use an OpenPandora to turn on my television set, since the OpenPandora does not have an infrared port.  I already have a dedicated HP 200LX to perform that function.

Having the feature that I described about having a low-power processor companion turn on the computer at a designated time is all about maximizing battery life. If a user does not need to have the OpenPandora in standby mode in order to trigger appointment alarms, then the user can choose to turn off the computer and know that it will still sound alarms.  Then, when the user actually wants to use the OpenPandora, the user will have more battery life to play games or do whatever else that they want to do with the computer. The lack of this timed power-on feature with long battery life is one of the things that makes most modern hand held computers not a complete replacement for an HP 200LX.

 

[WizardStan]

sudo su
echo unix_date_in_UTC > /sys/class/rtc/rtc0/wakealarm
exitFor example, if it is currently December 4th 2013 at 5:00pm EST, that means the UNIX timestamp is 1386194400. I want it to wake up at 6:00pm EST, timestamp 1386198000echo 1386198000 > /sys/class/rtc/rtc0/wakealarm

And then shut down or put the Pandora to sleep. At 6:00 PM EST (23:00 UTC) it will power on as if I had hit the power switch. The hardware clock sets a register which can be read by the kernel (which it currently doesn't do, but it can if you want to recompile the module) that will tell you what started it so you can know if it was powered on by a flick of the switch, being plugged into an outlet, or alarm triggered.

It does assume that there's an RTC output from the SoC that is properly wired to some wakeup on the PMIC

The PMIC *is* the RTC.

 

[Exophase]

For example, if it is currently December 4th 2013 at 5:00pm EST, that means the UNIX timestamp is 1386194400. I want it to wake up at 6:00pm EST, timestamp 1386198000

echo 1386198000 > /sys/class/rtc/rtc0/wakealarm

And then shut down or put the Pandora to sleep. At 6:00 PM EST (23:00 UTC) it will power on as if I had hit the power switch. The hardware clock sets a register which can be read by the kernel (which it currently doesn't do, but it can if you want to recompile the module) that will tell you what started it so you can know if it was powered on by a flick of the switch, being plugged into an outlet, or alarm triggered.

But if you shut the Pandora down does it really keep the RTC powered? Is the PMIC always powering the RTC? Does anyone know how long it takes the battery to fully drain when shut down?

 

[WizardStan]

But if you shut the Pandora down does it really keep the RTC powered? Is the PMIC always powering the RTC?

Sorry, check my edit. The TWL is more than just the charge chip, it's also the RTC and the PWM for all the LEDs (except the LCD backlight). It has a disturbing number of features which is why I think MWeston chose it.

Does anyone know how long it takes the battery to fully drain when shut down?

After 7 days of being off, my Pandora had gone from 100% to 92%. My estimate is 3 months of actually being off while the RTC ticks away. And yes, the RTC will wake the Pandora up from a completely off state, so long as there is battery life remaining (obviously).

 

[Exophase]

Guess that settles that then, thanks WizardStan.

 

[EssoAir]

I have been looking for a replacement for my HP 200LX palmtop computer.  Although the HP 200LX is not fast by modern standards, the HP 200LX can sleep for a month on a pair of AA batteries and then wake itself up to sound an appointment alarm or execute a program at a designated date and time.  For example, I have one of my HP 200LX computers set up to turn on the living room television, turn on the separate HDTV tuner, and change the channel to one of my favorite television shows once each week by running a program that sends infrared signals from the HP 200LX to the television set and the HDTV tuner.  I have another HP 200LX set up to back up its main memory contents to a compact flash card early each morning and charge the batteries if they need charging.


It would be useful to have a long standby alarm capability in a modern palmtop computer.  To maximize battery life, the computer would be completely shut down except for a processor companion.  The processor companion would have a real-time clock and nonvolatile memory to store the date and time of the next alarm.  At the appointed time, the processor companion would power on the main computer, and the main processor could run a calendar / appointment program or some other program, sound an alarm jingle, display a text reminder associated with the alarm, and load the nonvolatile memory of the processor companion with the next alarm date and time.  Such a palmtop computer could have more intelligence than typical alarm clocks by sounding wake-up alarms only on work days and not the weekends, for example.  If a person is traveling, then the person might not have easy access to a compatible electrical outlet in a foreign country or out in a field and might need to conserve battery life by shutting down the palmtop computer rather than putting it in standby or sleep mode.


Ramtron produced processor companions with a real-time clock and nonvolatile FRAM memory:

http://www.youtube.com/watch?v=vqja6qSvwyw


Cypress Semiconductor later acquired Ramtron.  A PDF file with information about one of their processor companion products is available at:

http://www.cypress.com/?rID=73539


While I do not know if the existing processor companions can do what I envision, it is an interesting possibility to consider.

So what you're saying is you spent $100 on a computer to turn in your TV which could have eqsily been accomolished with a $10 microchip?

 

[WizardStan]

Quiet you, some people like different toys