Boot sel pin not reading as high in software

[guru_prasanth]

Hi,

For LPC1876 microcontroller, we are connecting the boot sel GPIO 7[5] pin with pull up resistor.

In Oscilloscope we had checked, the voltage is exactly 3.3V.

But the software read value is 0.

For checking whether boot sel pin working or not, through JTAG we had configured the corresponding BOOT SEL pin as an output pin. And then we observed output voltage same as per the set value in software.

The same issue has happened in two of our boards.

Please help us

without boot sel pin we are unable to do anything.

[kerryzhou]

Hi Guru Prasanth,

     Are you sure you are using LPC1876 ? As I know, we don't have this chip.

   So, please double check your chip part number, then tell me again, I will help you to check the details.

  If the Oscilloscope already checked it is high, but the software read the pin is low, I think it is your code problem, you need to configure the GPIO function, and the select the according pin as GPIO, not other functions.  Take the LPC18XX series as an example, the ISP enter pin is P2_7, the Mode 0 is GPIO0[7], so you need to read the GPIO0[7].

Wish it helps you!

Have a great day,
Kerry

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