[lwip-users] Re: [lwip] Realtek RTL8019AS vs cs8900

[John C. Toman]

Hi Nishen,

The Rabbit 2000/3000 boards I've done a port for use the RTK8019AS. 
Unfortunately, the driver might not be of much use to you since it 
contains a lot of Rabbit assembly, some of which is necessary, and 
utilizes serial lines specific to the Rabbit architecture (i.e. this is 
not a generic RTK8019AS driver). You can take a look at 
http://ctica.com/RabbitTCPIP.jsp . The driver used doesn't use the 16 
bit mode, so I can't vouch for that. Also, the driver doesn't take 
advantage of an external interrupt to receive packets because that line 
isn't hooked up currently on any of the Rabbit Semiconductor core modules.

As for the relative advantages, I have heard that the cs8900 is a better 
design, but I don't have any evidence to back that up. They are both 
cheap, 10Mbit, bottom of the barrel ethernet chips. I can tell you that 
the RTK8019AS depends upon an EEPROM for its configuration (especially 
its MAC address). If the EEPROM isn't present (who wants to buy that 
part when you don't have to?), the line can be pulled up or the CPU can 
emulate the EEPROM if hooked up right. Both methods are a little messy 
and lead to a lot of initialization code but are commonly done. There 
are examples of both in the driver.

Regards,

John

Nishen Naidu wrote:

>Hi
>
>I just wanted to find out if anyone knows
>the advantages and disadvantages of using 
>Realtek RTL8019AS vs cs8900. (i.e. which
>one is better to use?)
>I would also like to find out if there is an 
>lwip port to use the Realtek RTL8019AS?
>Could someone please help?
>
>Thanks
>Nishen
>
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