Lpc2000

Hello,

You can use the 25MHZ clk from ENC28J60 to drive the
LPC. In this  case, you will "use the same clock
source for both ENC28J60 and the host controller..."

For LPC2292 you can have 25 or 50MHZ.

Adrian 

--- Ryan Niemi <ryan@...> wrote:

> Hello,
> 
> I'm working on a project that'll require ethernet. 
> I was hoping the
> LPC's w/ onboard MAC/PHY would come out before this
> project had to
> start, but alas, no such luck!  I've done the
> CS8900A, RTL8019A and
> Asix 10/100 routes before on past projects, but this
> application needs
> to be minimal space and lowest netlist connection
> count as possible to
> route in a minimally sized PCB.  Ethernet
> performance requirements
> isn't high, it'll just be some signalling and status
> packets to a
> control app over UDP.
> 
> Has anyone interfaced a Microchip ENC28J60 MAC/PHY
> to an LPC via SPI?
>  While looking at it, I ran across a potential
> problem.  The LPC2292
> datasheet section on the SPI interfaces say the SPI
> clock has a
> maximum of 1/8 the input clock.  The ENC28J60 errata
> says reading or
> writing the MAC registers may be unreliable if the
> SPI clock is below
> 8MHz.  At 60MHz, it would appear the max LPC SPI
> clock is 7.5MHz.  I'm
> contemplating overclocking the LPC slightly by using
> a 16MHz clock
> scaled to 64MHz, which would allow an 8MHz SPI
> clock.  But before I
> spend a bunch of time and money (it's a
> semi-personal project just for
> fun) to try it, I figured I'd check if anyone has
> blazed this trail
> before..
> 
> Alternatives were Cirrus EP9301/2, but the package
> is large and I
> still need an external PHY anyway.  Atmel AT91RM9200
> borders on cost
> sensitivity and also requires external PHY.  Not to
> mention external
> flash and RAM.  So I'm stuck with two chips minimum
> anyway, so might
> as well try to go with the LPC2292 as the most
> suitable CPU choice and
> select an ethernet solution around it.
> 
> -Ryan
> 
> 
> 
> 


Adrian Valeanu.
SC PROSAFE SRL
J/40/11835/2002 ; CUI 15026939
Aleea Politehnicii nr. 2
Bl. 5A, sc. 1 Ap. 17 Sector 6, BUCHAREST
ROMANIA
Tel/fax +40 (21) 781.38.58


		
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