topic Need to use pin PTA4 but not as NMI_b (KL15) in Kinetis Microcontrollers

Need to use pin PTA4 but not as NMI_b (KL15)

markosiponen — Mon, 29 Jul 2013 10:37:44 GMT

I need to use PTA4 as an GPIO input pin on a KL15 device. The pin can also be used for NMI_b. But I don't want to use the NMI_b signal (but it is the default setting, ALT7).

What do I need to think about?

Do I just need to configure PORTA_PCR4[MUX] = 1 (ALT1) and then also clear set FTFA_FOPT[NMI_DIS] = 0?

I see that the Processor expert doesn't clear the FTFA_FOPT[NMI_DIS] bit, it only set PORTA_PCR4[MUX] = 1. But then the NMI_b would be active for a short while after reset?

Re: Need to use pin PTA4 but not as NMI_b (KL15)

Hui_Ma — Tue, 30 Jul 2013 01:51:27 GMT

Hi,

You can disable NMI interrupt function via set FTFA_FOPT bit2 [NMI_DIS] value to 0b0.

The FTFA_FOPT register will load value from Flash address 0x40D during reset.

So, it need to program Flash address 0x40D with suitable value to disable NMI interrupt function.

In processor expert project, you could set 0x40D address value to disable NMI interrupt.

More detailed info, please check below picture.

Wish it helps.

B.R.

Ma Hui