Reading RTL8019AS registers

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Hello group,

Need some support from u people .....

We are trying to connect 89c51 8-bit controller to Realtek
Ethernet controller RTL8019AS. No external RAM is been used.
We have used Packet Wacker (Ethernet board) available from I would like to know the least and the necessary
connections required to kickstart the data transmission.

This is how we have connected....

1). SA0-SA4 connected to PORT2 - P2.0-P2.4
2). SD0-SD7 connected to PORT0 - P0.0-P0.7
3). INT0    connected to INT0  - P3.2
4). IOWB    connected to WR    - P3.6    
5). IOWR    connected to RD    - P3.7
6). AEN tied to VCC
7). JP  tied to VCC

To start with we tried to read the register 0x0A which contains
the Chip ID...but in vain. All we could read was 0xFF.

Also tried to write to the CR register with 0x21...and read from it.
Again wasn't able to read the correct value. what we read was 0xFF.

- How could we check our Realtek chip...?
- Is it proper to read the NIC's register without initialising it?
- Or do we require to recheck our
the board (Packet Wacker) comes with only few pins "out" for connection.

Thx in advance...

Lawrie Kurian

Re: Reading RTL8019AS registers

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IIRC, AEN is low active. If there is nothing else on the external bus, try
tying it low.


Tauno Voipio
tauno voipio @ iki fi

Re: Reading RTL8019AS registers
On 30 Sep 2003 06:13:58 -0700, (Lawrie Kurian)
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Quote from the datasheet (page 6, at the top):
"Address Enable. This ISA signal must be low for a valid I/O command."

Probably this is your problem.

Jan Dubiec,, mobile: +48 602 101787

Głęboka wiara wymaga płytkiego rozumu i nikłej wiedzy.

Re: Reading RTL8019AS registers
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Kurian) wrote:
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Thx for the reply...
AEN is actually connected to low.... i mis-wrote it on the post....
anyways..was able to solve the problem....
We weren't giving a 2ms pulse on thr RSTDRV pin of RTL8019AS.
After doing so... we were able to read the registers.

Lawrie Kurian.

Re: Reading RTL8019AS registers
In addition to previous posts :

I seem to recall that interrupt signals are active low on the 8051, so
you need an inverter between the RTL and the 8051.


Lawrie Kurian wrote:
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