ICSP Auto-Disconnect circuit?

[TheToasterBoy]

I noticed that the following PIC prototyping board has an interesting feature, an Auto Disconnect circuit / IC. It's for the in-circuit serial programmable PICs, such as the 16Fxxx.

http://www.basicmicro.com/Product.aspx?productID=93&CategoryID=35

(one of the two SOIC packages next to the DB9 connector, the other one is a MAX232 chipl)

I'm guessing it automatically isolates the RB6 and RB7 lines whenever the ISCP programmer brings MCLR up to the requisite programming voltage.

I've been using shunts to isolate the RB6 and RB7 lines manually for programming, but would love to make it automatic like the above proto board does.

Anybody have any ideas which IC or circuit they're using? My only guess is they're using one of Maxim's analog switches, such as the MAX4624:

http://www.maxim-ic.com/quick_view2.cfm?qv_pk=2116

Any suggestions, circuit fragments or part #s would be appreciated.

Thanks,

Ken

[xav27]

Hello Ken,

:Anybody have any ideas which IC or circuit they're using?

They use a 4053 wich is a simple "Triple 2-channel analog MUX/DEMUX"

esay to fnd and very low cost.

Hope it help you ?

Xavier

[TheToasterBoy]

Thanks. I ended up ordering the Basic Micro board Unfortunately I can't get them talking to each other now... just posted a new message.