Lpc2000

Hi Bill

I decided against the cs8900 since it is very big and 
needs 'simulated' bus lines with the LPC210x. It is also nice to be 
able connect to a 100MHz hub (not all can do 100 and 10), even if 
100M is not necessary for throughput.

I am using the MC9S12NE64 from Freescale - HC12 processor with 
onboard 10/100M LAN. 8k RAM and 64k FLASH - also cheaper than the 
cs8900 when I last compared.

I have the stack optionally running on this chip with the LPC210x 
simply requesting services (eg. UDP or TCP port) etc. via SPI. 
Otherwise I let the MC9S12NE64 run as simple LAN<->SPI converter for 
the stack in the LPC210x.

SPI between 2 processors is a bit sensitive since there is no DMA 
and this is a bottleneck restricting throughput to a couple of M 
bits/s.

I prefer to let the MC9S12NE64 do the stack since the throughput is 
much higher and the LPC210x doesn't need to bother with the details. 
The MC9S12NE64 can also take over other jobs since it has quite a 
few free ports, A/D converters, serial interfaces, I2C etc. As an 
extension to an LPC210x design it is very practical since it needs 
only SPI and an IRQ line.

A couple of questions: when you say you have external RAM and FLASH 
you can't be using an LPC210x - or are you reading and writing 
over 'simulated' bus lines? I do this for some simple peripherals 
but it is not very fast.

Regards

Mark Butcher

www.mjbc.ch

PS. I have written the stack myself to match with my Op-sys. Also it 
helps get really familiar with TCP/IP and all the internal workings. 
If something doesn't work properly you can't blame others for it...I 
decided to make it "IPV6 prepared" after looking at some open source 
versions which will need a thorough re-work to do this!

PPS The MC9S12NE64 has another advantage. By programming it to do 
LAN<->RS232 convertion it is possible to connect a PC via RS232 
(admittedly slow but not teh issue here) to a LAN/the INTERNET and 
debug the stack with real data in a comfortable environment (eg. 
Visual Studio) which allows a new service (eg. HDCP, DNS etc.) to be 
programmed and debugged in a very short time - say a day or so.

PPPS I am preparing a board for LPC210x and the new Microchip device 
(samples should be delivered shortly) so that I can see whether it 
has some advantages....




--- In lpc2000@yahoogroups.com, "Bill Knight" <BillK@t...> wrote:
> Mark
>   For free stacks there is lwip (also originally by Adam Dunkels).
> I have it running on an LPC w/ a cs8900.  Without the web pages
> it takes up about 50K of flash.  I have 256K of flash and a bunch
> of exteranl RAM so have not tried to optimize it for size.  Two
> smaller commercial alternatives are available from CMX and
> InterNiche.
> 
> BTW - what SPI based 100M LAN chip are you using??  I have heard
> of the one from MicroChip but I thought it was only 10BaseT and
> wasn't yet available.  There is also the W3100A from WizNET that
> is 10/100 but it's interface is the slower (400kbps) I2C.
> 
> Regards
> -Bill Knight
> R O SoftWare &
> http://www.theARMPatch.com
>