I apologize for asking such a dumb question but I am not trained in electronics and I grab circuits that others publish when they meet my needs and sometimes I can't figure out exactly which part to order. I see that it is a 100 nF cap but I need to order a part from Digikey and this is often where I get stuck. So maybe someone can tell me what type cap it is - ceramic, aluminum, film tantalum, etc. And how would I know this from the schematic? I prefer SMD parts if that makes a difference. Anything else I should know about it? Thanks for helping a software guy trying to do hardware.

 

Ceramic will be fine. Better frequency range than aluminum or tantalum.

 

100nF (0.1μF) is a common capacitor size which is often used for decoupling power supply rails and is typically ceramic since they are relatively small, cheap, and have good high frequency performance.
They are readily available in a SMD package.
It should be fine for you application also, as #12 stated.

 

I would scrap that circuit. What purpose does CH_PD serve?
What you need are 5V to 3.3V level shifters. You can read about various techniques here:

http://jamesreubenknowles.com/level-shifting-stragety-experments-1741

 

Thanks for your opinion. CH_PD resets the chip. Read the entire post here.

 

I would scrap that circuit. What purpose does CH_PD serve?
What you need are 5V to 3.3V level shifters. You can read about various techniques here:

http://jamesreubenknowles.com/level-shifting-stragety-experments-1741

Thank you for your opinion. CH_PD is the chip reset pin. You can read the entire post here.