Other Parts Discussed in Thread: DP83848T
Hello,
I'm devloping a board with STM32F407 with a DP83848T strapped to RMII mode in a transformerless configuration.
root.edab.nu/dropbox/ti/schematics.png
So far I got the management interface working and can read out the registers.
root.edab.nu/dropbox/ti/registers.png
The CRS line is currently not connected, so I think I will need to do that. However, for the moment I'm just looking at getting some reasonable signals on the tx/rx lines. What I see now, when I don't have anything connected is this, measured with a digital analyzer on pin 11, 12, 14, 15 of the PHY:
root.edab.nu/dropbox/ti/txrx_overview.png
root.edab.nu/dropbox/ti/txrx_single_message.png
I don't understand how I can have a signal on the RD line when I don't have anything connected to it?
The pulses are 2µs long, separated by 62µs.
On the ethernet side of it, the signals don't look any better.
If I connect a short unconnected cable, I get a "Remote Error" flag in the status register. I don't get any link indication if I connect it to something.
It's a bit messy but does anyone have an idea what can be the issue here?