Lpc2000

Guillermo Prandi wrote:
> Oh, I think I see the point, now. From what you say I get the
> following:
>
> 1) I have no choice but to go through the embedded bootloader for the
> initial programming.
>
You can use JTAG to upload your own code to RAM and execute this, so if 
you really do not want to use the philips bootloader you can use JTAG to 
do whatever you want. Philips uses this same method to program the 
bootloader and test the device. You also have an extra flash sector you 
can use if you are short on flash and like to do everything yourself.

> 2) Using the embedded bootloader should work if I am careful enough
> to provide the correct crystal frequency. However, as the writing
> procedure seems to be poorly implemented, a write-read-compare cycle
> should be considered.
>
Maybe philips chose to use a delay loop because the hardware bits were 
not reliable enough. Has anyone tested these hardware bits with 
diffirent core frequencies to see if they work ok? I would be happy to 
try some code if anyone has programmed their own flash programming routines.

> 3) I might get a non-functional unit if my program misbehaves and
> accidentally runs code that erases the provided bootloader. This
> is "unavoidable" since the processor lacks some kind of hardware
> protection to prevent this to happen accidentally.
>
If the bootloader is erased, the hardware should be accessable with 
JTAG, because there is no bootloader code to disable it.

> 4) I have the choice (however undocummented) to write my own
> bootloader. If this bootloader lacks flash memory programming
> capabilities I might be safer because my potentially misbehaving
> application will not be able to jump in the middle of the flash
> programming code and accidentally erase the bootloader or other parts
> of the flash.
>
Until now I have never seen a LPC2xxx with a trashed bootloader, so I am 
happy with what I have now.


> Correct me if I'm getting you wrong.
>
> Guille
>

Richard.