Lpc2000

Guillermo Prandi wrote:

>>This usually means that you disable interrupts or relocate
>>all your ISP routines into RAM.
>>    
>>
>
>Hi, Richard. I don't understand the "relocate all your ISP routines 
>into RAM" part. What ISP routines? Shouldn't disabling all interrupts 
>be enough?
>
>Guille
>
>  
>
A lot of Flash does this, while the microcode sequencer inside the flash 
memory is busy working with the flash array, it cannot be disturbed by 
the CPU core reading that same array.  Some flash memories are capable 
of allowing reading while the sequencer is busy writing / erasing some 
other part of the Flash array, but these types of Flash are more of an 
oddity than the normal flash you find.

So, to keep your CPU core running (waiting for the flash to become 
available again), you copy some code into RAM, then call the Flash erase 
/ write IAP routines from there.  This way, your CPU doesn't find itself 
suddenly reading random bytes from the Flash program store.

TomW


-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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