[En-Nut-Discussion] Meaning of the EEMU signal

[Harald Kipp]

Sorry, Matthias. I haven't been able to catch up with
all posts yet sent during holidays.

And sorry again for the confusion, which may result
from my previous post. I answered the wrong question
without switching on my brain.

In fact EEMU(A15) is held high during EEPROM emulation,
which indeed disables the RAM. If your board works
without using this line, fine. :-) But

     NICOUTB(NIC_CR, NIC_CR_STP | NIC_CR_RD2 | NIC_CR_PS0 | NIC_CR_PS1);
     NICOUTB(NIC_PG3_EECR, NIC_EECR_EEM0);

accesses the RTL8019 and I wonder how this should
work if A15 is floating.

Harald


At 16:41 08.01.2005 +0100, you wrote:
>Hello Tobias,
>
> >I'm trying to understand the EEPROM emulation in the
> >1.3G hardware for the RTL8019AS nic. I understand what
> >the EEDO(A14) and the EESK(A13) signals do but I dont
> >get the meaning of the EEMU(A15) signal.
> >In the schematic theres nothing special with this
> >signal. It only connects trough the inverter to the
> >SA15 pin of the RTL.
> >Does the RTL require a low on this line while reading
> >the contents of the EEPROM?
>
>I asked the same question before some days/weeks and got no response.
>
>I removed the code for the EEMU line and tested it: it works!
>
>I can't understand the meaning of that line.
>But they is not needed.
>
>
>Best regards
>
>Matthias
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