I'd like to build a hw watchdog for my laptop.
Does anybody knows if its possible by using the pcmcia port?
Or how could I archive this???
you can use the PCMCIA port, but I will not recoment it, the interface specfication for the PCMCIA interface is about 500 pages of things you have to consider, we just made a PCMCIA interface for a WLAN card on a ARM7 uPC, that was 4 persons in 4 month.
But anyway you will need to get a hand on the "small" book that describes the interface, and the you have almost direct acces to you adresse and data in you laptop, then you will have to do some lowlevel (i PC world it is lowlevel, in AVR it is standard) programming.
From the top of my head I do not remember if the reset for the computer is in the PC-Card (PCMCIA) interface...
The PC-Card interface are as default disablet (for hot swap), so you would need to do a work arround on this, it is normaly the PC-Card that tells the computer to turn on the power...
Why don't you use the printer port instead?
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Your talk about the PCMCIA specification is frightning... 500 pages??? I'm working on a senior design project where we are building a device that communicates thru a PCMCIA card. However we cannot find any information on that specification for less than $300. If you have the spec or know anyware we can find it would be extremely helpful.
*Through* a PCMCIA card or *as* a PCMCIA card? How set in stone is using PCMCIA? I would have thought USB or parallel port is a lot easier. (The USB spec is out there.)
A hardware watchdog usually resets the machine if it triggers. That's not normally a good idea with laptops, what are you intending to do? If you don't need the reset line then the other alternatives are possible.
Another possibility: If you can find the Compact Flash spec then you can get a PCMCIA adapter card very cheaply.
The specfications for the PC-Card is not complety frightning, but you want to be carefull when using it you most likly get somthing wrong down the line of development (that is normal, isen't is?), so I recoment to use an old computer for startup.
But on the specfications side, I'm sorry I can help we are under a NDA on the specfications, so you will have to buy it somewhere....
Usb, or Parallel would be easier, I agree.
But where else do I have access to a reset pin to the laptop???
(I don't like to open the laptop, so the ide-bus is out of reach)
The reset pin on the PCMCIA will not reset the laptop (IIRC), the reset line is to reset the hardware on the PCMCIA card that has been inserted. So no mater what implementation you use, you will still need to attach to the reset hardware of the mainboard via a jumper wire or switch.
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