topic Re: JM60 @ 3.3V? in 8-bit Microcontrollers

JM60 @ 3.3V?

ballen — Fri, 16 Oct 2009 22:43:03 GMT

I'm thinking of using the JM60 at 3.3V. The data sheet gives specs at 3V, so it must be ok, but I'm wondering why Vcc(typ) is listed at 5V. Are there any issues that aren't obvious? The only one that jumps out is the USB voltage regulator Vin(min) of 3.9V, which could easily be handled with a seperate supply.

Has anyone tried this? Anything unusual I should be aware of...?

Thanks,

bill

Re: JM60 @ 3.3V?

donw — Sat, 17 Oct 2009 03:57:26 GMT

The JM60 works at full speed @ 3v3 OK. No catches except

for the USB supply as you note. (Disable the on board regulator and feed in

3v3 through a regulator from the USB Volt feed).

I connect port G0 (the next pin along) to the USB power pin, so I get a keyboard interrupt

when the USB is plugged in.

Note also for USB operation you need an external xtal 1 to 4 mhz.

And don't forget to set the Low Volt Detector to the correct trip voltage!

Re: JM60 @ 3.3V?

ballen — Mon, 19 Oct 2009 20:40:25 GMT

Thanks, Don! Good idea on the KBI, too.

Bill