Strange behavior on P2.10

[lpcware]

Content originally posted in LPCWare by gclaudiu on Thu Feb 16 21:17:45 MST 2012
Hi there,

This is my first post here and I am also pretty new to this ARM development thing. Anyay, I am working on a small project that get a LPC1769 to talk with a OV7670. All is great and work fine except a small problem: I have setup an external interrupt on pin P2.10 to monitor VSYNC signal, which is working fine, however, when I try to compile and upload the code (debug mode) system basically hang, if I disconnect P2.10 from anything and do this is compiling and all working fine, connect it back after code uploaded on the board and everythng runs like it should, interrup working fine.

FYI, my setup is: LPCXpresso 1.4.5 IDE with LPC-Link attached to LPC1769 (LPCXpresso board), board and camera module powered through USB from LPC-Link.

Any idea why this happen? Is cause of using external interrupt or is something special about P2.10 pin that I may miss? Any suggestion will be appreciated. Thank you.

[lpcware]

Content originally posted in LPCWare by NXP_Europe on Sun Feb 19 15:47:12 MST 2012
Hello gclaudiu,

ISP is entered when the P2.10 = [U]EINT0[/U] is low as the reset is given.

see User Manual 10360:

[LEFT][FONT=Arial][SIZE=2][FONT=Arial][SIZE=2][I]Pin P2.10 is used as a hardware request signal for ISP and therefore requires special[/I][/SIZE][/FONT]
[SIZE=2][FONT=Arial][I]attention. Since P2.10 is in high impedance mode after reset, it is important that the user[/I][/FONT][/SIZE]
[SIZE=2][FONT=Arial][I]provides external hardware (a pull-up resistor or other device) to put the pin in a defined[/I][/FONT][/SIZE][/LEFT]
[SIZE=2][FONT=Arial][I]state. Otherwise unintended entry into ISP mode may occur.[/I][/FONT][/SIZE]
[/SIZE][/FONT]

[lpcware]

Content originally posted in LPCWare by gclaudiu on Thu Feb 16 22:42:46 MST 2012
Oops, sorry, i saw the answer already: P2.10 is used to go in ISP mode... ^_^
Thank you anyway.