Two SPI Signals for one?

Development Boards Arduino
1

Hi. I’m working on making a schematic for a project that I may get around to this summer.

The project is making a handheld console based off of an Arduino (Duemilanove/Uno). I’m using some of the schematics for multiple shields: the joystick shield, the LCD shield, and the SD shield. After looking through the schematics a few times, I noticed that the LCD and SD interfaces are both SPI.

How, or what part, would I use to put both the mentioned LCD and an SD socket into the design, since the Arduino (as far as I know) is only capable of using one SPI interface at any one time?

I was thinking of using relays or something, but I can’t figure out how the 8-channel Darlington optoisolator chip http://www.sparkfun.com/products/312 is set up. Can anyone shed some light on this please?

2

SPI is a three wire buss with an additional Chip select line for each device on the buss.

All you should need is to define two output pins, one for each SPI device and only enable the device being ‘talked’ to.

3

Thanks for the reply.

What would the name for that pin be in a schematic? Would that be the Sck pin?

4

Names for SPI are often:

DI - Data in (common to all devices)

DO - Data out (common to all devices)

SCLK - clock (common to all devices)

CS or CE - Chip select or chip enable (unique for each device)

5

Thanks for the replies, I was kind of confused there.