TIDA-060017: SPI Trace Lenght & Multiple Devices Single PCB

Hi,

SPI supports two multi-device topologies, daisy-chain and star. Daisy-chain topology splits the clock to route in parallel to the slaves. But, data remains point-to-point. The MISO of one slave goes to the MOSI of another, chaining them together. Which topology are you trying to implement?

The TIDA-060017 reference design showcases using LVDS to transmit SPI over long distance, https://www.ti.com/lit/ug/tidued8/tidued8.pdf, but it is for point-to-point only.

Thanks

David

Hi David,

I prefer star, as it’s all on one PCB and will be easier to manage the design I think.

I was looking at the reference design you listed, but I couldn’t understand how to split the slave end out to multiple devices. I have found an alternative brand of driver IC range which could solve the problem, but my go to is TI which I would prefer to stick to.

Thanks.

Hi,

The devices used in the reference design can support multidrop applications. So for SPI Star topologies, I wonder if you can use the LVDS multi-drop to implement this topologies as shown in below example, 

This app note goes into more detail on the LVDS Multidrop Connection, https://www.ti.com/lit/an/slla054a/slla054a.pdf

Thanks 

David