TMS320F28379D: 关于什么时候需要对GPIO上拉电阻进行设置

Dandi Zhang

Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

2837xD的技术手册中写道：上拉电阻默认是不使能的。用于在没有外部信号输入时将输入引脚的保持在已知的状态。(原文：GPIOAll pullups are disabled by default. Pullups can be used to keep input pins in known state when there is no external signal driving them.)

按照我的理解，当把GPIO作为输出时，不需要对于GPIO上拉控制寄存器进行设置，因为默认是不使能的。但是我在官网的C2000ware提供的例程中看到对EPWM进行GPIO设置时的程序如下：

void InitEPwm1Gpio(void)
{
    EALLOW;

    //
    // Disable internal pull-up for the selected output pins
    // for reduced power consumption
    // Pull-ups can be enabled or disabled by the user.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAPUD.bit.GPIO0 = 1;    // Disable pull-up on GPIO0 (EPWM1A)
    GpioCtrlRegs.GPAPUD.bit.GPIO1 = 1;    // Disable pull-up on GPIO1 (EPWM1B)

    //
    // Configure EPWM-1 pins using GPIO regs
    // This specifies which of the possible GPIO pins will be EPWM1 functional
    // pins.
    // Comment out other unwanted lines.
    //
    GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 1;   // Configure GPIO0 as EPWM1A
    GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 1;   // Configure GPIO1 as EPWM1B

    EDIS;
}