Re: Ethernet chip - newbie need help with selection
- From: "Fred" <fred@xxxxxxxxxxx>
- Date: Fri, 21 Oct 2005 11:39:01 +0100
"Howard Henry Schlunder" <howard_hs@xxxxxxxxx> wrote in message
news:43588d2f$1_4@xxxxxxxxxxxxxxxxxxxxx
> "zilinxchip" <zilinxchip@xxxxxxxxxxxxxxx> wrote in message
> news:pan.2005.10.21.07.50.09.637066@xxxxxxxxxxxxxxxxxx
>> Hello all,
>> I need a recommendation for an Ethernet chip. I plan to
>> integrate
>> it with an MCU (probably 8 bit). Either a PIC or an AVR.
>>
>> I've heard of the Realtek 8019AS. Is that a good chip to work with? Is
>> good
>> documentation and schematic examples available for it
>> (i've heard otherwise). Is it considered a little dated given that its
>> an
>> old chip?
>
> Although the Realtek 8019AS can be used, I consider it to be relatively
> crappy. It is doubtful that you will be able to get any useful
> information on the chip from Realtek, since it was originally designed for
> the ISA bus on standard PCs. However, because there aren't that many
> Ethernet controllers out there for embedded use, this non-PCI chip is
> relatively popular. The Microchip PICDEM.NET demo board's Users Guide has
> schematics showing it in use. Microchip App Note AN833 "The Microchip
> TCP/IP Stack" may be useful if you're wondering how to interface with the
> Realtek's ISA interface. I would provide links to the afformentioned
> documents, but unfortunately Microchip's website is down for maintenance
> right now.
>
> The cons of this chip are:
> 1. High pin count wastes board space and increases soldering work
> 2. ISA bus requires bit banging, diminishing performance
> 3. Chip is old and costs a lot
> 4. Data sheet is gobbledygook and incomplete (for the purposes of doing
> non-ISA-PC oriented designs)
>
> The pros of this chip:
> 1. It exists
> 2. It works at 5V
>
For micros with address and data bus there's nothing wrong with the deivce.
If you're into bit banging then perhaps the PCI variety may be more
appropriate. They're also cheaper. I'm talking of a couple of years ago
but I found an Asix part which was a Realtek lookalike with the same
registers etc. The datasheet give you a second stab at understanding how to
drive the chip.
>> If so, what others can you suggest? I'd like to use a chip which has
>> good
>> documentation/datasheets which I can refer to and more importantly
>> understand with ease.
>
> I'd recommend the Microchip ENC28J60 stand alone Ethernet controller with
> SPI. It's awesome compared to the 8019AS. The only significant problem
> is that the chip is new and Microchip's standard distributors don't appear
> to have any chips to sell you at this point. Unless you can wait, you may
> have to contact Microchip to obtain chips to play with.
>
> I've written a great deal of code for the ENC28J60 including my own TCP/IP
> stack. I like it.
Worrying - I hate things you can't get! It destroy any positive feature
the device might have.
.
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- From: zilinxchip
- Re: Ethernet chip - newbie need help with selection
- From: Howard Henry Schlunder
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