Lpc2000

John,

just wanted to acknowledge we got the message and are looking into 
it. Will provide feedback once it is through internal evaluation.

Philips Apps


--- In lpc2000@yahoogroups.com, "John Heenan" <l10@...> wrote:
>
> Below is a draft of a possible sensible formal request we could 
make 
> to Philips with regard to bootloader enhancement. It is simple and 
> practical. 
> 
> If Philips agrees we can use interrupts by copying interrupt 
> instructions and constant addresses to the start of RAM and 
setting 
> MEMMAP to RAM mode. We can still use IAP features of the 
bootloader. 
> 
> There is no sense in replacing the bootloader if you accept it 
does 
> its job as is: why chuck IAP when it works great and can be used 
to 
> advantage in an enhancement, such as with USB enhanced bootloading?
> 
> John Heenan
> 
> 
> Dear Philips
> 
> This is a formal request with regard to the bootloader of the 
LPC2xxx 
> series of microcontrollers.
> 
> We are requesting a small enhancement to the bootloader whose end 
> functionality is to 
> - give us an option to bypass the pin 0.14 test by the bootloader 
> when there has been an external reset
> - perform our own bootload tasks taking advantage of IAP if we 
want to
> - rejoin the bootloader informing the bootloader what we now want 
it 
> to do or what we have done
> 
> For existing LPC2xxx parts with flash based bootloaders we are 
> requesting you make an upgrade to the bootloader available to us.
> 
> For the bootloader to decide to bypass four items of information 
are 
> necessary
> 1. Whether to bypass
> 2. Where to bypass to (in supervisor mode expecting ARM 
instructions)
> 3. Where we need to return to if we want to return ('BX LR' is a 
good 
> option)
> 4. What should be specified in a register on return
> 
> On return perhaps R0 could have a value to indicate one of the 
above
> 
> - conduct a normal pin 0.14 test
> - bypass pin 0.14 test as if test is true 
> - bypass pin 0.14 test as if test was false
> - we have used IAP functions to conduct our own bootloading: 
please 
> restart the bootloader as if there was an external reset
> 
> Currently address 0x1FC is used to store the CRP value. If this 
value 
> is 0x8765 4321 (or 0x4321 8765) then Code Read Protection (CRP )is 
> enabled.
> 
> If CRP is not enabled then we request that if the CRP value is 
0x4321-
> --- or 0x----4321 where ---- represents four hexadecimal digits 
then 
> these hexadecimal digits be used to decide a multiple of 4kB to 
jump 
> to. For example if the CRP value is 0x4321 001E or 0x001E 4321 
then 
> this is interpreted to call address 0x1E (decimal 30) times 4kB = 
> 0x0007 B000. This is the start of sector 25 on the LPC2148 and is 
the 
> start of the last 8kB of flash on the LPC2148.
> 
> Given that no flash sector can be less than 4kB for erase purposes 
> (they are either 4kB or 32kB) then there is no advantage in 
> specifying a finer resolution than 4kB as a multiple for call 
purposes
> 
> This request has the support of the following members of the 
LPC2000 
> newsgroup on http://groups.yahoo.com/group/lpc2000/
> 
> John Heenan
> Add your name if you support such a request!
>