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Message

LPC2106: can I use P0.22-P0.30 as "output" with primary JTAG?

2006-05-09 by volodymyr_tymchyshyn

Hello,

I am using Olimex "LPC-P2106" board with JTAG pins P0.17-P0.21
(primary group).
I prototype with LCD, so I need almost all pins set as "out" or "io".
I there any trick to set pins P0.22-P0.30 (used for alternative JTAG
and Trace) to output mode, while using the JTAG debugging?
It looks like using them as "input" is not an issue (P0.31 is used for
button on "LPC-P2106") but they do not switch to "output" in Debug
mode. The JTAG shows the values of "direction" and "out" registers
changing properly, but actual levels on pins look to remain "input"...

I have written the application and it is working fine in "release"
mode (executed from flash), but I'd like to have debug possibility and
also run it from RAM...

The UG (page 79) says "Function control for the pins P0.17-P0.31 is
effective only when the DBGSEL input is pulled low during Reset".
Actually it looks like the pins are set as GPIO at reset, but the
IODIR setting to output has no effect with DBGSEL=1 during Reset...


Thanks for help!

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