LXT971A problem

We use the LXT971A on an MPC8250, and it works well. Did you remember to put pullup resistors on the LED/CFGn pins (see tables 7 and 9 in the data sheet)?

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Greg Neff VP Engineering

we use 2 leds to display network trafic. these 2 LED/CFG are pull up to 2,2V and the last one is pull up to 3,3V I don't know if this voltage is enough to put input to high position. You know, don't you ??? Thanks for your help.

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Greg Neff VP Engineering

I don't know what you mean. I can't pullup the 2 pins to 3,3V because I use it to display the network trafic : it is plugged to a led. Tomorrow, at office, I will see all that and I let you know about that. Thanks. See you

When you said 'pulled up to 2.2V' I assumed that you meant to a 2.2V supply.

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Greg Neff VP Engineering

no, there is a LED and a resistor betweeen pin and 3,3V

Hi,

I'm at office, and I'm seeing in configuration register (adress 0) that the 3 LED/CFGn pins are in high state: Speed select, A/N enable and Duplex mode are at 1. So it's ok for this point.

I've found the problem. The sleep mode is enable by hardware pin (which is pullup). If I disable this mode by soft, the hotplug feature is working. But it's not the solution because in datasheet, I see that the device can be waked up from sleep mode if there is activity on the connetor (so by plugging an ethernet cable). In my case, the device is not waked up. Why ??? I don't know

Any ideas ???