Lpc2000

As I mentioned I am a newbie to this processor.

I am currently waitng for my development tools but have larely finished 
my circuit diagram, and need to deal with this pin.

As a matter of principle I like to have firware upgrade capablity in my 
products via a serial port. (Its difficult to otherwise access hardware 
embedded in 1/2 an inch of epoxy!)

I appreciate that this bit (and a reset) give access to the boot loader. 
Is is also possible to jump into the boot loader from a running program. 
If so what is the entry address and what conditons must I set up before 
I do. I expect to reset the program afterwards.

Thanks

Owen Mooney

At 02:30 PM 3/8/04 +1300, you wrote:
>I am currently waitng for my development tools but have larely finished
>my circuit diagram, and need to deal with this pin.
>
>As a matter of principle I like to have firware upgrade capablity in my
>products via a serial port. (Its difficult to otherwise access hardware
>embedded in 1/2 an inch of epoxy!)
>
>I appreciate that this bit (and a reset) give access to the boot loader.
>Is is also possible to jump into the boot loader from a running program.
>If so what is the entry address and what conditons must I set up before
>I do. I expect to reset the program afterwards.

If you are not going to reprogram the whole chip you could use the IAP 
facility.  If you are going to do the whole chip (or the boot area) I would 
want to have access to the ISP pin in any case if only as a fall back for 
the cases when the programming gets interrupted and leaves you with no 
valid program.  I've seen that behaviour on several boards even without 
potting.  Add potting and Murphy is going to get might tempted ;)

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III

The way I intend to do things is like I have done on many other 
products.

The flash will comprise 3 major regions:
* Philips ISP loader
* My "bootloader" the flash sector at address 0)
* "Application area" (the rest of flash)

Port 0.14 is wired such that it is normally pulled high, but with a 
test point to allow it to be pulled low. During manufacturing, the 
programming/test station has a test jig which pulls this pin low to 
force the ISP mode. The flash is then programmed with my bootloader 
and the application.

Once disconnected and rebooted, the code will execute my bootloader. 
This has two roles:
* Firstly it does a checksum over the entire "application area". [ie. 
similar in concept to the Philips bootloader checksum, but more 
thorough] If the checksum fails or
* a break is detected,

then the bootloader will go int o the firmware upgrade mode to allow 
the "application area" to be reprogrammed. Flash programming is done 
with "In Application Programming" (IAP) described in Philips AN10256.

If the checksum is OK and there is no break, then the "applicaion" is 
executed (ie. jump to first address in "application area").

--- In lpc2000@yahoogroups.com, Owen Mooney <ojm@s...> wrote:
> As I mentioned I am a newbie to this processor.
> 
> I am currently waitng for my development tools but have larely 
finished 
> my circuit diagram, and need to deal with this pin.
> 
> As a matter of principle I like to have firware upgrade capablity in 
my 
> products via a serial port. (Its difficult to otherwise access 
hardware 
> embedded in 1/2 an inch of epoxy!)
> 
> I appreciate that this bit (and a reset) give access to the boot 
loader. 
> Is is also possible to jump into the boot loader from a running 
program. 
> If so what is the entry address and what conditons must I set up 
before 

> I do. I expect to reset the program afterwards.
> 
> Thanks
> 
> Owen Mooney

Are there any non-obvious considerations in using an external oscillator
to drive the clock pin of the LPC210X (instead of a crystal using the
internal oscillator)?

It capacitively couples at a low level.  It is not a direct connect
from the oscillator to the pin on the LPC.

Regards
-Bill Knight
R O SoftWare



On Mon, 8 Mar 2004 13:00:18 -0500, James Dabbs wrote:

Are there any non-obvious considerations in using an external oscillator
to drive the clock pin of the LPC210X (instead of a crystal using the
internal oscillator)?




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> It capacitively couples at a low level.  It is not a direct
> connect from the oscillator to the pin on the LPC.

So, if I need to clock the LPC from an external oscillator, what should
I do?  In this case, it's actually an sine waye from a UHSO, but I was
planning to square it up for this chip.

--- In lpc2000@yahoogroups.com, "James Dabbs" <jdabbs@t...> wrote:
> > It capacitively couples at a low level.  It is not a direct
> > connect from the oscillator to the pin on the LPC.
> 
> So, if I need to clock the LPC from an external oscillator, what
should
> I do?  In this case, it's actually an sine waye from a UHSO, but I
was
> planning to square it up for this chip.
I use an 3.3V oscillator IC and use a resistor divider (330 Ohms from
the oscillator to a common point, 75 Ohms from the common point to
ground).  I then run a 100pf cap from that sommon point to the X1
input of the processor. 

Robert

--- In lpc2000@yahoogroups.com, "James Dabbs" <jdabbs@t...> wrote:
> > It capacitively couples at a low level.  It is not a direct
> > connect from the oscillator to the pin on the LPC.
> 
> So, if I need to clock the LPC from an external oscillator, what
> should I do?  In this case, it's actually an sine waye from a UHSO,
> but I was planning to square it up for this chip.

Check out page 39 in the LPC210x User Manual (download from
Philips website).  It shows you exactly how to do it.  Basically,
you need to put a 100pF capacitor between your oscillator and
X1.  The oscillator should have an amplitude of at least 200mV
and no more than 1.8v.

    -bob