RMII MII Help Please

- B
- Blip
  
  Contact options for registered users
posted
15 years ago

Wed, Sep 3, 2008 2:22 AM

Note: I also posted this to c.a.embedded. I'm not sure it belongs here, but no answers there so far...

In putting together a little control nodule w/ a single 10/100 ethernet port, I started wondering if I need to pay any attention to the RMII. IIRC (& it seems that there is not much that I do anymore), I built some working 10Mbit - realtek based - boards w/o ever paying any attention to RMII.

However, somewhere I read that this spec defines communications between the MAC & the PHY.

Again, using the realtek (8019as) chip (or even national chips) reads & writes occurred over DMA between the chips & a PIC. Do I have to pay attention to RMII only on multiple (hub or switch) eth port configurations or always? If someone can clear this up for me, I'd appreciate it.

Thanks, Tom

Loading thread data ...

- M
- Marris
  
  Contact options for registered users
Vote on answer
posted
15 years ago

Sat, Sep 6, 2008 5:20 PM

Tom, It's not clear what you are trying to do from your post.

RMII is a way to connect a PHY chip to MAC chip. You only need to worry about RMII if you are doing a PCB layout. You need to choose a MAC and PHY chip that both support the same MAC/PHY interface. For 10/100 this can be MII, RMII or SMII. So if both your MAC and PHY chip support RMII you simply connect the relevant pins together on your PCB.

Arthur.

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.