[vdr] Re: Power board

[Guido Fiala <gfiala@s.netic.de>]

> imho the best device would be a combination of a timer with a
> programable infrared receiver (like irman). so you could wake up by
> timer or by a specific ! infrared command (not any - cause in the
> usual living room there are a couple of ir controlable devices and we
> dont want the vdr machine to react to there commands).
> afaik wake on ring shoud work with most bios´es.
>
> this combination would save serial ports too.

Yep - although i did'nt thought of an IR-receiver the first (i do not use IR 
so far).
Is such an receiver required or can one just use the PIC itself to detect 
some short byte-sequence? Eventually that might save power (from the 
battery), as the PIC runs with 15uA at 32kHz @2V. (A Lithium battery would 
last several years).

Once the system is running the PIC could retransmit the IR-data to the serial 
port.

About USB: Are there as much control-lines as required?
The PIC-programmer (serp) uses RTS, CTS, TXD, DTR & GND, RXD & RI would be 
required for above. Some changes have to be done to the suggested circuitry 
(which PIN for which use) there.

A simple 24bit SW timer based on the prescaled hardware-timer of the PIC 
16C84 could be used to store the next wake-up event. The PIC would have to 
scan for signals at TXD and some Portpin the IR-Receiver is connected to, 
assuming not to different IR-baud-rates it should work.
Beside the chip less than a dozen components.

Geometrically it's a bit more difficult: if anything is in the plug - how can 
the IR signals reach (typical) the backside of the casing?