Forums

LPC213x And Ethernet

Started by dsidlauskas1 January 25, 2005
On 26 Jan 2005 at 18:08, Rick Collins wrote:

>
>
> --- In , "dsidlauskas1" <dsidlauskas@w...>
> wrote: > > I have a project where the LPC312x fits very well accept
> that there's > a requirement for ehternet connectivity. I'd appreciate
> any > suggestions as to how this might be accomplished cheaply and
> simply.
>
> I am looking at doing something very similar with the AT91SAM7S chips.
> Like the LPC312x parts, there is no external data bus. I think this
> is the biggest issue. It means you will either need to add a serial
> to parallel interface chip of some sort (possibly an FPGA) or you will
> have to bit bang the bit IO ports to talk to the Ethernet chip.
>
> The more I think about this, the more I like using an FPGA to provide
> a fast serial port to the ARM chip and a parallel port to a LAN91C111
> chip. I am discussing this in the AT91SAM7 group. I expect most of
> this discussion will be applicable to the LPC21xx chips too.
>
> http://groups.yahoo.com/group/AT91SAM7/
>


If you really need ethernet on a chip without external bus-interface, then
using the Wiznet W3100A, makes much more sense. It alread has an
I2C interface and runs the TCP/IP stack in hardware for upto 4 simultaneous
connections. If you want to connect it using the parallel bus, it has a mode
where it needs only 2 address lines, 8 data lines, Read, Write, interrrupt and
Chip Select. A total of 14 pins. If you want more than 4 simultanoues connections,
then you have to have a complete TCP/IP stack as with other ethernet controllers. Regards
Anton Erasmus
--
A J Erasmus



Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet

An Engineer's Guide to the LPC2100 Series


--- In , "Anton Erasmus" <antone@s...> wrote:
> If you really need ethernet on a chip without external
bus-interface, then
> using the Wiznet W3100A, makes much more sense. It alread has an
> I2C interface and runs the TCP/IP stack in hardware for upto 4
simultaneous
> connections. If you want to connect it using the parallel bus, it
has a mode
> where it needs only 2 address lines, 8 data lines, Read, Write,
interrrupt and
> Chip Select. A total of 14 pins. If you want more than 4
simultanoues connections,
> then you have to have a complete TCP/IP stack as with other ethernet
controllers. That may be one solution, but I don't see how you can say it makes
"much more sense". I2C is very slow compared to even 10 Mbps. The
SSC port on the AT91SAM7S parts will operate at speeds above 10 Mbps
and will add much less latency and boost throughput than an I2C
connection. The FPGA will be on the board anyway, so it seems natural
to use it to make the connection to the Ethernet chip.




Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
On 29 Jan 2005 at 17:50, Rick Collins wrote:

>
>
> --- In , "Anton Erasmus" <antone@s...> wrote: >
> If you really need ethernet on a chip without external bus-interface,
> then > using the Wiznet W3100A, makes much more sense. It alread has
> an > I2C interface and runs the TCP/IP stack in hardware for upto 4
> simultaneous > connections. If you want to connect it using the
> parallel bus, it has a mode > where it needs only 2 address lines, 8
> data lines, Read, Write, interrrupt and > Chip Select. A total of 14
> pins. If you want more than 4 simultanoues connections, > then you
> have to have a complete TCP/IP stack as with other ethernet
> controllers. > That may be one solution, but I don't see how you can say it makes
> "much more sense". I2C is very slow compared to even 10 Mbps. The
> SSC port on the AT91SAM7S parts will operate at speeds above 10 Mbps
> and will add much less latency and boost throughput than an I2C
> connection. The FPGA will be on the board anyway, so it seems natural
> to use it to make the connection to the Ethernet chip.
>

In your previous posts you said you are considering ADDING a FPGA to enable
you to easier / faster access a ethernet controller using a MCU without external
bus. If you already have an FPGA, and it has enough spare capacity, then it
makes sense to use it. Even if you can use SPI interface which is in the order
of 5MHz, it will also be a lot slower than the ethernet's 10MB/s. The overhead of
accesing a normal ethernet chip together with all the data you have to handle
as part of the TCP/IP stack means that you will not get that high a speed overall.
With the Wiznet chip, even though the I2C is fairly low speed, you ONLY need to
transfer data you actually are going to use in your app. The TCP/IP stack overhead
is handled within the Wiznet chip. Hence the ethernet interface has got no overhead
asociated with it, until there is data for the specific socket you have opened.
In a previous message someone pointed to an Olimex LPC board, together with
one of these Wiznet chips, where they could serve web pages using the I2C
interface at 350kb/s if I recall correctly. using 14 port pins to emulate a parallel
interface, should be even faster.

Regards
Anton Erasmus
--
A J Erasmus



Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet

--- In , "Anton Erasmus" <antone@s...> wrote:

> In your previous posts you said you are considering ADDING a FPGA to
enable
> you to easier / faster access a ethernet controller using a MCU
without external
> bus.

Boy, leave it to engineers to nit pic. But if you reread my message,
that is not what I said. I said I would "use" an FPGA to do the
conversion.

> If you already have an FPGA, and it has enough spare capacity, then
it
> makes sense to use it. Even if you can use SPI interface which is in
the order
> of 5MHz, it will also be a lot slower than the ethernet's 10MB/s.

I didn't say I would use SPI. The Atmel SAM7 chips have an SSC port
which is similar to the serial ports on DSP chips and will interface
directly to many codecs at very high speeds, >10 Mbps.

> The overhead of
> accesing a normal ethernet chip together with all the data you have
to handle
> as part of the TCP/IP stack means that you will not get that high a
speed overall.
> With the Wiznet chip, even though the I2C is fairly low speed, you
ONLY need to
> transfer data you actually are going to use in your app. The TCP/IP
stack overhead
> is handled within the Wiznet chip. Hence the ethernet interface has
got no overhead
> asociated with it, until there is data for the specific socket you
have opened.
> In a previous message someone pointed to an Olimex LPC board,
together with
> one of these Wiznet chips, where they could serve web pages using
the I2C
> interface at 350kb/s if I recall correctly. using 14 port pins to
emulate a parallel
> interface, should be even faster.

Certainly this is interesting. But like I said, it is a far cry from
10 Mbps. The overhead is not that great and regardless of how much
overhead you have, the time required to transfer the data across the
CPU/LAN chip interface will still add to that. So having a 20x higher
interface speed is still a significant boost.




Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
On 30 Jan 2005 at 6:30, Rick Collins wrote:

>
>
> --- In , "Anton Erasmus" <antone@s...> wrote:
>
> > In your previous posts you said you are considering ADDING a FPGA to
> enable
> > you to easier / faster access a ethernet controller using a MCU
> without external
> > bus.
>
> Boy, leave it to engineers to nit pic. But if you reread my message,
> that is not what I said. I said I would "use" an FPGA to do the
> conversion.

:-) Yes, I have been involved in many HUGE arguments between engineers,
where someone made a statement, and because of some sort of slip misused
a word without realising it. Everybody else picks up on this, and even though they
fully agree with what the other guy meant to say, they do not agree with what
he actually said. Non-Technical people who listen to this, find this totally beyond
comprehension.

Anyway, I accept your argument.

> > If you already have an FPGA, and it has enough spare capacity, then
> it
> > makes sense to use it. Even if you can use SPI interface which is in
> the order
> > of 5MHz, it will also be a lot slower than the ethernet's 10MB/s.
>
> I didn't say I would use SPI. The Atmel SAM7 chips have an SSC port
> which is similar to the serial ports on DSP chips and will interface
> directly to many codecs at very high speeds, >10 Mbps.
>
> > The overhead of
> > accesing a normal ethernet chip together with all the data you have
> to handle
> > as part of the TCP/IP stack means that you will not get that high a
> speed overall.
> > With the Wiznet chip, even though the I2C is fairly low speed, you
> ONLY need to
> > transfer data you actually are going to use in your app. The TCP/IP
> stack overhead
> > is handled within the Wiznet chip. Hence the ethernet interface has
> got no overhead
> > asociated with it, until there is data for the specific socket you
> have opened.
> > In a previous message someone pointed to an Olimex LPC board,
> together with
> > one of these Wiznet chips, where they could serve web pages using
> the I2C
> > interface at 350kb/s if I recall correctly. using 14 port pins to
> emulate a parallel
> > interface, should be even faster.
>
> Certainly this is interesting. But like I said, it is a far cry from
> 10 Mbps. The overhead is not that great and regardless of how much
> overhead you have, the time required to transfer the data across the
> CPU/LAN chip interface will still add to that. So having a 20x higher
> interface speed is still a significant boost.
>

The higher speed serial interface would definitaly help. What is the cost of the ethernet
controller you have in mind compared to the Wiznet W3100A chip ? If the pricing are
similar, it might still be worthwhile using the Wiznet chip in parallel mode via the FPGA
and high speed serial combination. To get bootstrap code going to re-program or boot
the board via ethernet needs very little code because of the hardware TCP/IP stack. If
one then uses an RTOS or something else with a full TCP/IP stack, then one can use
the W3100A chip as a normal type ethernet chip. Opening a TCP/IP socket using the
W3100A takes something like 20 lines of C code.

Regards
Anton Erasmus --
A J Erasmus



Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
Re: LPC213x And Ethernet

Do you really need the extra memory of the 2138? Why not spend
about the same money for an LPC with an external memory bus? That
would provide (I believe) the fastest possible parallel interface to
the ethernet chip. Or am I missing something? It seems really
weird to go through a third chip (FPGA) with a serial interface when
what you are after is speed.
James

--- In , "Anton Erasmus" <antone@s...> wrote:
> On 30 Jan 2005 at 6:30, Rick Collins wrote:
>
> >
> >
> > --- In , "Anton Erasmus" <antone@s...>
wrote:
> >
> > > In your previous posts you said you are considering ADDING a
FPGA to
> > enable
> > > you to easier / faster access a ethernet controller using a MCU
> > without external
> > > bus.
> >
> > Boy, leave it to engineers to nit pic. But if you reread my
message,
> > that is not what I said. I said I would "use" an FPGA to do the
> > conversion.
>
> :-) Yes, I have been involved in many HUGE arguments between
engineers,
> where someone made a statement, and because of some sort of slip
misused
> a word without realising it. Everybody else picks up on this, and
even though they
> fully agree with what the other guy meant to say, they do not
agree with what
> he actually said. Non-Technical people who listen to this, find
this totally beyond
> comprehension.
>
> Anyway, I accept your argument.
>
> > > If you already have an FPGA, and it has enough spare capacity,
then
> > it
> > > makes sense to use it. Even if you can use SPI interface which
is in
> > the order
> > > of 5MHz, it will also be a lot slower than the ethernet's
10MB/s.
> >
> > I didn't say I would use SPI. The Atmel SAM7 chips have an SSC
port
> > which is similar to the serial ports on DSP chips and will
interface
> > directly to many codecs at very high speeds, >10 Mbps.
> >
> > > The overhead of
> > > accesing a normal ethernet chip together with all the data you
have
> > to handle
> > > as part of the TCP/IP stack means that you will not get that
high a
> > speed overall.
> > > With the Wiznet chip, even though the I2C is fairly low speed,
you
> > ONLY need to
> > > transfer data you actually are going to use in your app. The
TCP/IP
> > stack overhead
> > > is handled within the Wiznet chip. Hence the ethernet
interface has
> > got no overhead
> > > asociated with it, until there is data for the specific socket
you
> > have opened.
> > > In a previous message someone pointed to an Olimex LPC board,
> > together with
> > > one of these Wiznet chips, where they could serve web pages
using
> > the I2C
> > > interface at 350kb/s if I recall correctly. using 14 port
pins to
> > emulate a parallel
> > > interface, should be even faster.
> >
> > Certainly this is interesting. But like I said, it is a far cry
from
> > 10 Mbps. The overhead is not that great and regardless of how
much
> > overhead you have, the time required to transfer the data across
the
> > CPU/LAN chip interface will still add to that. So having a 20x
higher
> > interface speed is still a significant boost.
> >
>
> The higher speed serial interface would definitaly help. What is
the cost of the ethernet
> controller you have in mind compared to the Wiznet W3100A chip ?
If the pricing are
> similar, it might still be worthwhile using the Wiznet chip in
parallel mode via the FPGA
> and high speed serial combination. To get bootstrap code going to
re-program or boot
> the board via ethernet needs very little code because of the
hardware TCP/IP stack. If
> one then uses an RTOS or something else with a full TCP/IP stack,
then one can use
> the W3100A chip as a normal type ethernet chip. Opening a TCP/IP
socket using the
> W3100A takes something like 20 lines of C code.
>
> Regards
> Anton Erasmus > --
> A J Erasmus




--- In , "Anton Erasmus" <antone@s...> wrote:
> :-) Yes, I have been involved in many HUGE arguments between
engineers,
> where someone made a statement, and because of some sort of slip
misused
> a word without realising it. Everybody else picks up on this, and
even though they
> fully agree with what the other guy meant to say, they do not agree
with what
> he actually said. Non-Technical people who listen to this, find
this totally beyond
> comprehension.
>
> Anyway, I accept your argument.

I am glad you appreciate this. I don't bother with pointless internet
arguments these days, but still it is nice to come to a friendly
agreement without hassle. :) > The higher speed serial interface would definitaly help. What is the
cost of the ethernet
> controller you have in mind compared to the Wiznet W3100A chip ? If
the pricing are
> similar, it might still be worthwhile using the Wiznet chip in
parallel mode via the FPGA
> and high speed serial combination. To get bootstrap code going to
re-program or boot
> the board via ethernet needs very little code because of the
hardware TCP/IP stack. If
> one then uses an RTOS or something else with a full TCP/IP stack,
then one can use
> the W3100A chip as a normal type ethernet chip. Opening a TCP/IP
socket using the
> W3100A takes something like 20 lines of C code.

I understand that the W3100A would be simpler to use, but I believe
you said it did not support 100 base TX, right? The LAN91C111 is not
an inexpensive chip, but it includes the PHY so all you need to add is
the transformer and the connector and that end is ready to plug into a
network. Yes, it needs a lot more on the other side, but making a
general app board, I want to be able to support 100 base TX. Even if
you don't need the data rate, this can be an advantage is some cases
and it should still meet the selling price target of $99, qty 1.

I will need to project a parts list in the next couple of days, now
that I have been promised samples of the AT91SAM7S64. This is pin
compatible with the SAM7S128 and SAM7S256 and will do for initial
prototypes.




Re: LPC213x And Ethernet
Re: LPC213x And Ethernet
> I understand that the W3100A would be simpler to use, but I believe
> you said it did not support 100 base TX, right? The LAN91C111 is not
> an inexpensive chip, but it includes the PHY so all you need to add is
> the transformer and the connector and that end is ready to plug into a
> network.

One advantage of the 91C111: You can disable the internal Phy.
So it should be possible to connect a WiFi Phy. Or am I wrong here ?

> Yes, it needs a lot more on the other side, but making a
> general app board, I want to be able to support 100 base TX.

And 10MB might die .... even the HCS12 with Ethernet support 100MB
(MCS9S12NE64). --
42Bastian Schick




Re: LPC213x And Ethernet
On 31 Jan 2005 at 5:07, Rick Collins wrote:

[Lots of stuff snipped]
>
> I understand that the W3100A would be simpler to use, but I believe
> you said it did not support 100 base TX, right? The LAN91C111 is not
> an inexpensive chip, but it includes the PHY so all you need to add is
> the transformer and the connector and that end is ready to plug into a
> network. Yes, it needs a lot more on the other side, but making a
> general app board, I want to be able to support 100 base TX. Even if
> you don't need the data rate, this can be an advantage is some cases
> and it should still meet the selling price target of $99, qty 1.
>
> I will need to project a parts list in the next couple of days, now
> that I have been promised samples of the AT91SAM7S64. This is pin
> compatible with the SAM7S128 and SAM7S256 and will do for initial
> prototypes.

No the W3100A does support 100 base T. Although you need a seperate
PHY and of course the magnetics + connector. They have a module which
includes the W3100A device + the Realtek RTL8201L Phy. One only need
to add the magnetics. If you actually use the module, then you can offer
the board without the module at a reduced price, and people can later
add it. Nice when one is on a tight budget.

Regards
Anton Erasmus

--
A J Erasmus



Hi All

I am presently working on an Ethernet extension for the LPC2106 with
the Freescale (Motorola) MC9S12NE64. I bought 5 pieces for about $12
a piece in 80 pin housing (volume obviously much less) for
experimenting.

50MHz 64k FLASH, 8k RAM, 10/100Mb EMAC/PHY SCI, 2xserial, A/D, I2C
etc.

I'm still new to the chip but have just got it pinging with my OpSys
and ARP/IP based on OpenTCP using the GNU compiler.

The idea is to use the SCI to interface and let the NE64 do some of
(or all) the stack work.

Compared to a solution with MicroChip ENJ28J60 (which I may also
try):
- can do stack and other jobs if required
- Needs programming
- slightly bigger footprint
- Can do 100Mb
- Less RAM - can only do 1k5 frames
- Has MII interface if required
- Don't know the price of the MicroChip solution at the moment but
probably similar..

Is any one doing similar?

Regards

Mark Butcher

www.mjbc.ch