lpcware

ISP pin

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by jdurand on Thu Sep 06 14:00:11 MST 2012
I've noticed on several different parts the pin that is pulled low to enter ISP by default has a pullup resistor like most pins.  But, the user manual says the pin is floating and needs an external pullup.

I normally put the pullup on my boards but was wondering which was correct.

I understand if there's a lot of capacitance on the pin that it might not come up fast enough, but with the standard RESET input (10K external pullup + 0.1uF capacitor) I would think in almost all cases the ISP pin would be high long before the RESET was released.

Is this correct?

Outcomes