Lpc2000

Limited time at the moment but here are highlights:

1)  USB - does not meet the USB spec. in several areas.  No endpoint 
pairing. limited endpoint numbering. VERY awkward interface. 
Incorrect documentation or correct documentation with incorrect 
operation....

2)Timers.  Registers need to be set in a specific sequence. This not 
documented but we learned this from taking apart the C code.  The 
timers reset to FFFA ??? of all things and the timers can't be 
triggered on less then 5 (=0000-fffa).

3)SPI - there are bugs and there is no documentation! Works in master 
mode but slave is unpredictable. The problem I think we had was the 
slave select signal not meeting some timing requirements.  ST agreed 
that was likely. There are no timing specs. 
After enough emails and calls this is what I got from ST FAE:

>by experiment: SS must be low before the first active clock edge.
>Setup time is less than 24nS. These are not the official datasheet 
>numbers but found thru experimentation. SS must also be low during 
>setup of the slave port library call:
>
>       /* Configure the clock to be active high */
>          BSPI_ClkActiveHigh(BSPI1,ENABLE);
> 
>       I also found this thru experimentation.
 

4)Clock system - 3 clocks.  each peripheral has it's own max clock. 
so you need to mix and match.

5) No serial port ISP.

6) 6 extra pins and 3 extra caps for the core's 1.8V supply

7) The 1.8V Core backup supply(required) is not very useful since the 
minimum RAM retention voltage is 2.7V

8) the STR71 requires external clocks (not crystals).  Needs two if 
you want USB

On the plus side, there are complete libraries that work well - 
mostly. In contrast the example code is not clear and not commented 
(I want to read example code - not decode it)

If you check the STR71x forum, you will find several instances of the 
ST ARM expert moderators explaining that something has already been 
fixed in the next lib release, and then users begging for the release 
to be released.  In general I think the ST forum (or the LPC2000)
would be a good place to do research to separate fact from marketing.

ST is new to ARM7 and their STR71 parts remind me of the early PICs 
in their ridiculously complex peripheral interface.  Documentation is 
very poor

The majority of the problems we had were related to the peripherals 
but there are hardware issues too. I would suggest investigating the 
implementation details of any design that might be applied to the 
STR7.

Sorry, that became a bit of a rant.

Ian

--- In lpc2000@yahoogroups.com, rob@u... wrote:
>
> 
> Ian,
> 
> > Sorry, not an answer to your question but my experience with the 
STR7
> > made me switch to the LPC2148 half way through a project.  The 
STR7s
> > are very buggy and have little or no documentation and each 
> > peripheral is overly complicated.  I would suggest a careful look 
at
> > the STR7 details before you jump in (power supply,clock system, 
USB,
> > Timers, SPI ...)  
> 
> Normally I prefer the LPCs, but right now I'm working on a STR7xx
> design. Can you elaborate on the STR7xx problems that you have had?
> You can email me privately if you wish. (Or reply here to let people
> know why the LPC is better...)
> 
> I'd like to get any warnings of problems that I can BEFORE I spend a
> big chunk of time finding them myself.
> 
> -Rob
> www.usbmicro.com
> 


> > --- In lpc2000@yahoogroups.com, Herbert Demmel <dh2@d...> wrote:
> >>
> >> Hi Guys,
> >> 
> >> does anybody have some information when the LPC23xx chips will 
come
> > out?
> >> 
> >> Currently the only ARM7 with external bus + USB + flash + RAM is 
> > the STR7 
> >> as far as I know. I have to plan resources for a upcoming new 
> > product, so I 
> >> really would like to know, when one can get samples of this chip.
> > It has 
> >> been already announced a long time ago to come in the 2nd quarter
> > of 2005 ...
> >> 
> >> Regards
> >> Herbert Demmel
> >> 
> >> ----------------------------------------------------------
> >> demmel products
> >> Radnitzkygasse 43
> >> A-1100 Vienna / Austria / Europe
> >> Voice: +43-1-6894700-0
> >> Fax: +43-1-6894700-40
> >> Email: dh@d...
> >> WWW: http://www.demmel.com
> >>
> 
> 
> 
> 
> 
> 
> 
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