LPC2214 External Memory Connection

Sorry if I double post, not sure if I press submit or preview by mistake…

Anyways,

HI, I’m new to the whole ARM thing and I just received my first development board. BUT this board has no external memory but it does have the pin to connect to some. So I’m building a memory board for it. My question is…

  1. I’m planning to add 2Mb of flash to it and have the option of later (soldering on another 2Mb) the question is, for the Chip Select Pin (CS) Do I have to tie them together or does each memory have to have a separate CS line? ie. The first flash is tied to CS0 and the second Flash is CS1 or can they both be CS0?

  2. I’m planning to upgrade the on board crystal to 25Mhz, is memory speed going to be an issue, I mean do I need to fine a 30ns or faster flash?

Thanks.

PS.

The ARM is a LPC2214.