EK-TM4C123GXL: Dual Function Pins

Charles Moher

Just putting a first project together on this board and noticed 4 pins are doubled up. For example PD0 and PB6. Is the upper listing the default or something ? Do I have to do anything in code to select one over the other if I use these ?

over 3 years ago

0 Charles Tsai over 3 years ago

TI__Guru**** 191886 points

Hi Charles,

Yes, most pins can be configured to bring out different functionality. For example, PB6 can be used for SSI2RX (SPI receive pin), M0PWM0 (a PWM pin) or T0CCP0 (a input capture pin). To use PB6 for a particular function, you will need to configure the pin. Please refer to the various examples in TivaWare library for illustration. Let's look at the example in C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c123gxl\pwm_invert. If you open up pwm_invert.c file you will find the below two lines of code that configure PB6 as the PWM pin.

//
// Configure the PWM function for this pin.
//
MAP_GPIOPinConfigure(GPIO_PB6_M0PWM0);
MAP_GPIOPinTypePWM(GPIO_PORTB_BASE, GPIO_PIN_6);

0 Ralph Jacobi over 3 years ago

TI__Guru*** 135355 points

Hello Charles M.,

You may be referring to the resistor tying PD0/PB1 together - if so see this FAQ: https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1020817/faq-ek-tm4c123gxl-how-to-resolve-unexpected-behavior-on-pins-pd0-pd1-pb6-and-or-pb7/3772683#3772683

You can remove the resistors in pretty much all cases.

Best Regards,

Ralph Jacobi

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EK-TM4C123GXL: Dual Function Pins