Hi,
I'm designing a board to input four audio signals, amplify them, and run them through an ADC. I have two newbie questions about this. This is the first real board I've designed (I've designed simple arduino shields before) but I'm a high school student with no real electrical engineering training.
1) The chip (ADS1274 by TI) uses SPI for communication. (Frame-sync also available, but I'm using SPI. Everything I've done with SPI in the past has had four pins, SCLK, MISO, MOSI, and SS. This chip doesn't quite. It has DOUT pins as the MISO, and SCLK pin, no MOSI (doesn't matter, probably just means it's a read-only device). But, it doesn't have a SS pin at all. I can't figure out how to use an SPI device that doesn't have an SS pin. There's a DRDY pin that, by their diagrams, seems to send the same signals as the master SS pin usually would. But, since the ADS1274 is obviously a slave device, this isn't helpful. What do I do? Can I just use it without SS???
2) An even more newbie question. The ADS1274 requires a CLK input (no surprise). I just don't know how to wire it up to a device like this. I have embedded crystals on to an ATMega chip before which has two clk-related pins, but the ADS1274 only has one CLK input. How do I connect it?
Thanks for putting up with my dumb questions!
-Seth