Unpowered Laptop ICSP external power

[mslaney]

My laptop is unable to provide the required power for an unpowered pic programmer. Is there a way I can provide external power to this device? Is it just a matter of powering the chip while programming? My thought was to make a 'Y' cable that uses my serial port for programming and the USB port for power. There is plenty of power on my USB but it is only +5.
I'm using the Olimex PG2 and 1 programmers.

[Luciano]

Hi Mike!

(I have not tested this solution, be careful
with your RS232 port and USB port).

Laptop Computer Serial Port Power Booster:
http://www.qsl.net/eb4eqa/serial_boo...al_booster.htm

Where to get +5V from USB:
http://www.siliconchip.com.au/cms/A_30612/article.html


Best regards,

Luciano

[mslaney]

Yes, that seems like the sort of thing I need. The max203 is probably good enough since I only need one RS232 for this project. It doesn't need external caps so it will take up even less space. I could just put a little board in the same place I put the junction between the USB and the DB9.

Thanks for the link!

[arthurok]

that chip just increases the amount of current availible on the rs232 lines .
you need a little switching up converter my
programmer uses a similar approch to boost the usb voltage
5 vlts for the programmer and up conversion to generate the 13 vlt vpp " how about using 2, 9 vlt batteries in series???"
i run pics from a 9 vlt battery with a low drop out regulator you can just run the battery down another trick would be to use a maxim up converter chip "just needs a little inductor"
with some of the new maxim chips they have such a large
voltage range that i could run the battery down to 3 vlts before the 5 vlts stops regulating actually the newer pic chips dont even require a voltage regulator and have built in brown out detection so
the pic 16-f870 will operate between 2 and 5.5 vlts
so you could use 3 1.5 vlt battery in series and just let them run down.
if you need auxillary ics use 4000 series cmos and that
will work down to 3 vlts "i like gutless wonders"