The app note here:
http://www.esacademy.com/software/flashmagic/resources/AN10258_2.pdf
I have programmed a MCB900 with the ISP to ICP bridge code and made all the connections shown in this datasheet (and verified them).
There is some confusion, however:
On page 7, it says "To control VDD, a PNP transistor is needed, because P2.3 cannot supply enough current for the LPC9xx during programming."
On the following page, a nice schematic shows a 2n2222 being used, which is of course an NPN.
So which is it? NPN or PNP?
Or put another way, when designed, was VDD intended to be applied to the application with 2.3 being driven high or low?
To add to this confusion, an older version of the appnote shows a PNP transistor in the schematic.
Thanks,
Bruce
http://www.esacademy.com/software/flashmagic/resources/AN10258_2.pdf
I have programmed a MCB900 with the ISP to ICP bridge code and made all the connections shown in this datasheet (and verified them).
There is some confusion, however:
On page 7, it says "To control VDD, a PNP transistor is needed, because P2.3 cannot supply enough current for the LPC9xx during programming."
On the following page, a nice schematic shows a 2n2222 being used, which is of course an NPN.
So which is it? NPN or PNP?
Or put another way, when designed, was VDD intended to be applied to the application with 2.3 being driven high or low?
To add to this confusion, an older version of the appnote shows a PNP transistor in the schematic.
Thanks,
Bruce