topic Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0? in Kinetis Microcontrollers

WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

nidhintomy — Mon, 17 Oct 2022 05:52:16 GMT

My leds are on when led pin (eg. PTA16 - LED Green) is connected to PTB0 ( J2[1] - J2[10] are shorted ).

From data sheet PTA16 and PTB0 are default disabled.

1. Then how this is happened ?

2. What line of code should i used to solve this issue ?

Best Regards,

Nidhin

Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

Robin_Shen — Mon, 17 Oct 2022 08:43:11 GMT

Hi Nidhin,

Did you check the value of PTB0?

Best Regards,
Robin
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Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

nidhintomy — Tue, 18 Oct 2022 04:50:54 GMT

Hi @Robin_Shen

The Voltage at PTB0 = 1.5V

I erase the KW36. But still led is ON.

Best Regards,

Nidhin

Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

Robin_Shen — Tue, 18 Oct 2022 06:05:32 GMT

I don't know why you connect PTA16-PTB0. The voltage of PTB0 will light the GREEN LED. You can have a look at the circuit of LEDs.

Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

nidhintomy — Tue, 18 Oct 2022 10:19:13 GMT

Hi @Robin_Shen

I have a adc sample project in which i use PTB3 as adc input. The led3(red led) is on when i give input to pin PTB3. Due to led3 on i will get less voltage to adc input.

How to avoid this type of conflict with led?

Also, how to disable or make voltage 0 in pin PTB0?

Best Regards,

Nidhin

Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

Robin_Shen — Wed, 19 Oct 2022 06:15:43 GMT

Please use other external ADC input without other circuits.

If you want to light up the LED when the ADC input is higher than the voltage, please change the output of LED control pins after read the ADC result.

Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

nidhintomy — Thu, 20 Oct 2022 10:48:56 GMT

Hi @Robin_Shen

PTB0 pin can be configured as I2C0_SCL.

Does the voltage at PTB0 affect the I2C functionality ?

Best Regards,

Nidhin

Re: WHY KW36 LED IS ON WHEN LED PIN CONNECTED TO PTB0?

Robin_Shen — Fri, 21 Oct 2022 05:20:17 GMT

no. I2C pins need those external pull-up resistors.