Lpc2000

Hello,

does somebody made experience to use embedded Java and µCLinux on this 
chip.
I try to figure out what I need. O.K. µCLinux is easy but where I can 
get a stripped down java (for free) for this ARM7 chip.
I want to use a MMC card as a hard disk, write a little bootloader to 
load µClinux and then Java.

An other question is how to debug with an wiggler and Java (wich IDE 
Eclipse ???).
I'm thankfull for all inputs.

Cheers

Thomas

> does somebody made experience to use embedded Java and µCLinux on this
> chip.
> I try to figure out what I need. O.K. µCLinux is easy but where I can
> get a stripped down java (for free) for this ARM7 chip.

Useful JVM Performance Chart:
http://www.gumstix.org/tikiwiki/tiki-index.php?page=java

http://wiki.java.net/bin/view/Linux/AlternativeJavaVMsSDKs

I think you'd need an ARM with an MMU to run any of the normal Java
interpreters (ie JamVM, kaffe etc). However, there is this:

http://www.rtjcom.com/home.html

It can't be compared to a regular JVM but it allows you to use
Java semantics on a small MMU-less MCU.

  -- Doug

> > does somebody made experience to use embedded Java and µCLinux on this
> > chip.
> > I try to figure out what I need. O.K. µCLinux is easy but where I can
> > get a stripped down java (for free) for this ARM7 chip.
> 
> Useful JVM Performance Chart:
> http://www.gumstix.org/tikiwiki/tiki-index.php?page=java
> 
> http://wiki.java.net/bin/view/Linux/AlternativeJavaVMsSDKs

This runs uClinux and implements Waba:
http://www.linuxdevices.com/news/NS7588348856.html
http://waba.sourceforge.net/

I really don't think any of those JVMs will work on ARM7TDMI without MMU.
Perhaps on an ARM720T with lots of RAM. Even on X-Scale with 64MB most of
the JVMs are slow. The simple real-time java I mentioned can run in 18-24k
RAM without MMU. But is it Java? Sort of ....

  -- Doug




Joel Winarske wrote:

>>Useful JVM Performance Chart:
>>http://www.gumstix.org/tikiwiki/tiki-index.php?page=java
>>
>>http://wiki.java.net/bin/view/Linux/AlternativeJavaVMsSDKs
>>This runs uClinux and implements Waba:
>>http://www.linuxdevices.com/news/NS7588348856.html
>>http://waba.sourceforge.net/
>>

> I really don't think any of those JVMs will work on ARM7TDMI without MMU.
> Perhaps on an ARM720T with lots of RAM. Even on X-Scale with 64MB most of
> the JVMs are slow. The simple real-time java I mentioned can run in 18-24k
> RAM without MMU. But is it Java? Sort of ....

uClinux is for devices without a MMU.

Yeap,

I understood guys. Thanks for the input.
I'm really unsure what to do.
The best would be I put the 2294 in the garbage and switch to an 
ARM9 with MMU.
But then I don't have trouble anymore with C or C++ or JAVA. I'll 
buy a WinCe lic. for 3 Euros and I will program with MS.NET and 
Platform Builder.

But I don't want to do this because of "Bill".

But on the other hand I don't have so much time to develop my 
datalogger / controller and the price will grow like hell when I'm 
uisng ARM9 technologie and it's oversized.

I' newbiew in C and I don't want to learn ASM. I know, C#,JAVA,VB 
and SQL very well.
That's why I'm looking for a JAVA / µCLinux solution amd examples of 
this combination with JTAG.

Thanks

Thomas


--- In lpc2000@yahoogroups.com, Doug Sutherland <doug@p...> wrote:
>
> I really don't think any of those JVMs will work on ARM7TDMI 
without MMU.
> Perhaps on an ARM720T with lots of RAM. Even on X-Scale with 64MB 
most of
> the JVMs are slow. The simple real-time java I mentioned can run 
in 18-24k

> RAM without MMU. But is it Java? Sort of ....
> 
>   -- Doug
> 
> 
> 
> 
> Joel Winarske wrote:
> 
> >>Useful JVM Performance Chart:
> >>http://www.gumstix.org/tikiwiki/tiki-index.php?page=java
> >>
> >>http://wiki.java.net/bin/view/Linux/AlternativeJavaVMsSDKs
> >>This runs uClinux and implements Waba:
> >>http://www.linuxdevices.com/news/NS7588348856.html
> >>http://waba.sourceforge.net/
> >>
>

Joel Winarske wrote:
 > uClinux is for devices without a MMU.

Yes but it's often used on devices with MMU. Gumstix (PXA255) for example.
You need lots of ram to run these interpreters. Even on an ARM720T with
MMU and boatloads of ram it would be very slow. The guy who put together
those JVM performance numbers warned its slow on 400Mhz x-scale with 64MB.

What I'm wondering wrt java is where I can find a full implementation of
the JVM and class libraries running on ARM926EJ-S with ARM's jazelle
executing bytecode on silicon. Anyone know of such a thing?

  -- Doug

Joel,

yeah you're right. µCLinux is for devices w/o MMU. Thats the point, 
like Doug said. This OS is not memory save. Java could do everything. 
Is like in C (I believe) the developer must clean the memory because 
of the missing GC.

Thomas

--- In lpc2000@yahoogroups.com, "Joel Winarske" <joelw@i...> wrote:
>
> > I really don't think any of those JVMs will work on ARM7TDMI 
without MMU.
> > Perhaps on an ARM720T with lots of RAM. Even on X-Scale with 64MB 
most of
> > the JVMs are slow. The simple real-time java I mentioned can run 
in 18-24k

> > RAM without MMU. But is it Java? Sort of ....
> 
> uClinux is for devices without a MMU.
>

thomas_ploeger wrote:
 > yeah you're right. \ufffdCLinux is for devices w/o MMU.

Blackfin DSP with MMU boots uclinux. Gumstix with MMU uses uclinux.
There are countless other examples. Perhaps it was made for MMU-less
devices but in practice its used as a trimmed linux. Read the pages
on those VMs and you'll see it running on i386, PowerPC, PXA255, etc.

  -- Doug

> yeah you're right. µCLinux is for devices w/o MMU. Thats the point,
> like Doug said. This OS is not memory save. Java could do everything.
> Is like in C (I believe) the developer must clean the memory because
> of the missing GC.

If you don't want to touch C in your embedded micro project you might look
at some of these options:  http://jstik.systronix.com/compare.htm

Joel

O.K I'll check it out.

Thanks Thomas


--- In lpc2000@yahoogroups.com, Doug Sutherland <doug@p...> wrote:

>
> thomas_ploeger wrote:
>  > yeah you're right. µCLinux is for devices w/o MMU.
> 
> Blackfin DSP with MMU boots uclinux. Gumstix with MMU uses uclinux.
> There are countless other examples. Perhaps it was made for MMU-less
> devices but in practice its used as a trimmed linux. Read the pages
> on those VMs and you'll see it running on i386, PowerPC, PXA255, etc.
> 
>   -- Doug
>

> thomas_ploeger wrote:
>  > yeah you're right. µCLinux is for devices w/o MMU.
> 
> Blackfin DSP with MMU boots uclinux. Gumstix with MMU uses uclinux.
> There are countless other examples. Perhaps it was made for MMU-less
> devices but in practice its used as a trimmed linux. Read the pages
> on those VMs and you'll see it running on i386, PowerPC, PXA255, etc.

Thanks for pointing this out Doug.

On Tuesday 13 December 2005 08:51, Doug Sutherland wrote:
> Joel Winarske wrote:
>  > uClinux is for devices without a MMU.
>
> Yes but it's often used on devices with MMU. Gumstix (PXA255) for example.
> You need lots of ram to run these interpreters. Even on an ARM720T with
> MMU and boatloads of ram it would be very slow. The guy who put together
> those JVM performance numbers warned its slow on 400Mhz x-scale with 64MB.
>
> What I'm wondering wrt java is where I can find a full implementation of
> the JVM and class libraries running on ARM926EJ-S with ARM's jazelle
> executing bytecode on silicon. Anyone know of such a thing?

AFAIK, there are some ARM proprietary issues with Jazelle which mean it can't 
be included in the Linux codebase. AFAIK, you need to get a Jazelle license 
from ARM.

I know it isn't "real Java", but has anyone considered/tried TinyVM? This is 
the Java VM used for the Lejos programming environment for Lego Mindstorms. 
This is written for H8S, but most of it is C code and should be portable.