[sdiy] self-modifying code was: Re: My latest project

[Tom Wiltshire]

On 18 Feb 2010, at 10:21, Neil Johnson wrote:

> Hi,
>
> cheater cheater:
>> Out of curiosity: how difficult is it to keep program data in RAM?
>
> If its Harvard then you cannot execute code in data RAM.  The ARM- 
> based micros (e..g NXP family) are VonNeumann so you can execute  
> from the internal RAM, which is handy during development (fast run- 
> debug-reload cycle).

The dsPIC *is* a Harvard architecture, Neil's right. You can't run  
code from RAM. You wouldn't have enough space even if you could, mind...

You *can* reprogram the flash memory from a running program (as Neil  
suggested), but flash write-cycle lifetime is definitely an issue,  
particularly on the 33F parts I'm using, which only give 1000 cycles  
on the spec.

T.