LPC11C24 ISP Status LED

[matthewfilibert]

I'm making a board for the LPC11C24 and was wondering what the best way to implement a status LED would be when the device is in ISP mode? Do the pins default to pull up in ISP mode? I noticed that most pins are at 3.3V, however the current is very small as the pins are probably set as inputs.

[kerryzhou]

Hi Matthew Filiberti,

    1. ISP mode

      You need to check the condition that enter in the ISP mode at first.

   Actually, you don't need to use the LED, because when you give the condition, the chip will enter in the according ISP mode.

  If you still want to use the LED. You can use PIO0_1 as the LED light signal.

  As you know, if you enter LED mode, you need to keep PIO0_1 to low level during reset, so you can connect a LED, which is light with low level, and connect it to PIO0_1.

    2. pins default to pull up 

     Yes, after reset, most pins are in input and pullup enable mode.

    You can check the chpater 7, IOCONFIG register.

    You will find, after reset, pull up is enabled in default.

    Take an example:

 

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Kerry

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