Re: Re: R6k and Ethernet current

Steve Trigero <seecwriter-/[email protected]>
Newsgroups gmane.comp.hardware.rabbit-semiconductor
Message-ID <[email protected]>
We pretty much copied the Ethernet connections that are 
on the RCM6xxx Interface Board that comes with the RCM6700
Dev Kit. There is no pull-down on the Link line in their
design. Unless I'm missing something, all the Link signal 
does is drive the green LED, so I'm not sure how a pull-down 
will help my situation. What value pull-down did you use?


Steve




>________________________________
> From: mario_wtbbh <mario_wtbbh-/[email protected]>
>To: [email protected] 
>Sent: Wednesday, October 3, 2012 7:45 PM
>Subject: [rabbit-semi] Re: R6k and Ethernet current
> 
>
>  
>I'll grab an ethernet variant later today and will check. (Ours is permanently connected to a camera via an Ethernet x-over cable, so always has a connection).
>
>Long shot: Did you include the pulldown on Pin-7 (Lnk) "Needs ext pulldown on RCM5700/5750/6700/6750"?
>
>Regards,
>Mario
>
>--- In [email protected], "seecwriter" <seecwriter@...> wrote:
>>
>> For the RCM67XX module, we've noticed an anomaly with current draw
>> when using Ethernet.
>> 
>> When the Ethernet port is connected to a LAN, the total current draw
>> for the computer section (motherboard + RCM67XX) is a steady 350ma.
>> However, if the Ethernet port is not connected, the current fluctuates
>> between 350ma and 500ma. We've traced the increase in current to the
>> call of pd_havelink() that occurs at about a 500ms rate. That 150ma of 
>> extra current seems like a huge increase just to check for a LAN 
>> connection. This pulsing current is affecting our ADC and DAC readings 
>> and settings.
>> 
>> This occurs on all of our modules. Anyone else notice this and/or have
>> any ideas on what to do about it? Adding extra bypass caps hasn't 
>> helped. 
>> 
>> Steve
>>
>
>
> 
>
>
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