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Monday, February 11, 2008

NoTouch method ( LPC932 )

this work as a NoTouch implementation for the LPC932

This is the NoTouch implementation for the LPC932

execute the following when the external ISP stimuli (such as a UART string, switch press or whatever) occur:

mov a,#2

mov r5,#1

mov R7,#3

lcall 0ff00h

Then the program hums happily till the next power-on-reset after which it is in 'virgin chip boot mode' i.e. it will expect and accept FlashMagic input.

This can be automated further by engaging the watchdog after the code above and let it time out generating the reset. By that, in combination with a 'unique serial string activate', you can create a system that requires nothing more than connect the serial cable and run the PC.

This way a simple Rxd/Txd 232 chip (externally) connected to the PC is all that is required as opposed to the 'cut the power, bang the reset' etc that a pure hardware ISP entry require.

It is recommended that, during development, you include the above very early in the code activated by e.g. TXD held low. This will allow simple ISP activation when your code has a bug that does not let it reach the ‘customer activation’.

NOTE: when the chip comes from the factory it will automatically go to ISP, so no ‘first time mode’ is required.

Erik


Ref: http://www.8052.com/users/erikm/

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