Enable and Disable GPIO's in 28335

Kuldeep Kumar Mynampati

Hi,

I have programmed to GPIO pins from GPIO-0/1/2/3/4/5 which are PWM1A/1B, PWM2A/2B and PWM3A/3B.

1. When I want to disable the PWM's 1/2/3, I am setting the following GPIO pins to LOW that is GPIO0/1, GPIO2/3 and GPIO4/5 bit to 0. I am not sure whether I need to set the

GPIO control registers everytime to perform. Can I use

GpioDataRegs.GPACLEAR.bit.GPIO0 = 0; // SET INPUT TO LOW

GpioDataRegs.GPASET.bit.GPIO1 = 1; // SET INPUT TO HIGH. without performing on GPIO control registers? Please clarify?

Code:
{
    // PWM1a & PWM 1B are set to ZERO in GPIO Pin 0 and 1.
    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO0       = 1;   // Enable pulldown on GPIO0   PWM-1A
    GpioCtrlRegs.GPAMUX1.bit.GPIO0      = 0;   // GPIO0 = GPIO0
    GpioCtrlRegs.GPADIR.bit.GPIO0       = 1;   // GPIO0 = output
    EDIS;
    GpioDataRegs.GPACLEAR.bit.GPIO0     = 0;   // SET INPUT TO LOW.

    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO1       = 1;   // Enable pulldown on GPIO1   PWM-1B
    GpioCtrlRegs.GPAMUX1.bit.GPIO1      = 0;   // GPIO1 = GPIO1
    GpioCtrlRegs.GPADIR.bit.GPIO1       = 1;   // GPIO1 = output
    EDIS;
    GpioDataRegs.GPACLEAR.bit.GPIO1     = 0;   // SET INPUT TO LOW.


    // PWM2A & PWM 2B are set to ZERO in GPIO Pin 2 and 3
    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO2       = 1;   // Enable pulldown on GPIO2   PWM-2A
    GpioCtrlRegs.GPAMUX1.bit.GPIO2      = 0;   // GPIO2 = GPIO2
    GpioCtrlRegs.GPADIR.bit.GPIO2       = 1;   // GPIO2 = output
    EDIS;
    GpioDataRegs.GPACLEAR.bit.GPIO2     = 0;   // SET INPUT TO LOW


    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO3       = 1;   // Enable pulldown on GPIO2   PWM-2B
    GpioCtrlRegs.GPAMUX1.bit.GPIO3      = 0;   // GPIO3 = GPIO3
    GpioCtrlRegs.GPADIR.bit.GPIO3       = 1;   // GPIO3 = output
    EDIS;
    GpioDataRegs.GPACLEAR.bit.GPIO3     = 0;   // SET INPUT TO LOW


    // PWM3A & PWM 3B are set to ZERO in GPIO Pin 4 and 5
    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO4       = 1;   // Enable pulldown on GPIO2   PWM-3A
    GpioCtrlRegs.GPAMUX1.bit.GPIO4      = 0;   // GPIO4 = GPIO4
    GpioCtrlRegs.GPADIR.bit.GPIO4       = 1;   // GPIO4 = output
    EDIS;
    GpioDataRegs.GPACLEAR.bit.GPIO4     = 0;   // SET INPUT TO LOW


    EALLOW;
    GpioCtrlRegs.GPAPUD.bit.GPIO5       = 1;   // Enable pulldown on GPIO2   PWM-3B
    GpioCtrlRegs.GPAMUX1.bit.GPIO5      = 0;   // GPIO5 = GPIO5
    GpioCtrlRegs.GPADIR.bit.GPIO5       = 1;   // GPIO4 = output
    EDIS;
    GpioDataRegs.GPACLEAR.bit.GPIO5     = 0;   // SET INPUT TO LOW

}

2. Secondly, I want to set PWM1A to LOW and PWM1B to HIGH. Similary for PWM2A/3A to LOW and PWM2B/3B to HIGH. Below is the code.

function:

// PWM1A is set to ZERO and PWM1B is set to HIGH on GPIO Pin 0 and 1.
EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO0       = 1;   // Enable pulldown on GPIO1   PWM-1A
GpioCtrlRegs.GPAMUX1.bit.GPIO0      = 0;   // GPIO0 = GPIO0
GpioCtrlRegs.GPADIR.bit.GPIO0       = 1;   // GPIO0 = output
EDIS;
GpioDataRegs.GPACLEAR.bit.GPIO0     = 0;   // SET INPUT TO LOW.

EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO1       = 1;   // Enable pulldown on GPIO1   PWM-1B
GpioCtrlRegs.GPAMUX1.bit.GPIO1      = 0;   // GPIO1 = GPIO1
GpioCtrlRegs.GPADIR.bit.GPIO1       = 1;   // GPIO1 = output
EDIS;
GpioDataRegs.GPASET.bit.GPIO1       = 1;   // SET INPUT TO HIGH.

// PWM2A is set to ZERO and PWM2B to HIGH in GPIO Pin 2 and 3
EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO2       = 1;   // Enable pulldown on GPIO2   PWM-2A
GpioCtrlRegs.GPAMUX1.bit.GPIO2      = 0;   // GPIO2 = GPIO2
GpioCtrlRegs.GPADIR.bit.GPIO2       = 1;   // GPIO2 = output
EDIS;
GpioDataRegs.GPACLEAR.bit.GPIO2     = 0;   // SET INPUT TO LOW


EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO3       = 1;   // Enable pulldown on GPIO3   PWM-2B
GpioCtrlRegs.GPAMUX1.bit.GPIO3      = 0;   // GPIO3 = GPIO3
GpioCtrlRegs.GPADIR.bit.GPIO3       = 1;   // GPIO3 = output
EDIS;
GpioDataRegs.GPASET.bit.GPIO3       = 0;   // SET INPUT TO HIGH

// PWM3A is set to ZERO and PWM3B is set to HIGH in GPIO Pin 4 and 5
EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO4       = 1;   // Enable pulldown on GPIO4   PWM-3A
GpioCtrlRegs.GPAMUX1.bit.GPIO4      = 0;   // GPIO4 = GPIO4
GpioCtrlRegs.GPADIR.bit.GPIO4       = 1;   // GPIO4 = output
EDIS;
GpioDataRegs.GPACLEAR.bit.GPIO4     = 0;   // SET INPUT TO LOW

EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO5       = 1;   // Enable pulldown on GPIO5   PWM-3B
GpioCtrlRegs.GPAMUX1.bit.GPIO5      = 0;   // GPIO5 = GPIO5
GpioCtrlRegs.GPADIR.bit.GPIO5       = 1;   // GPIO5 = output
EDIS;
GpioDataRegs.GPASET.bit.GPIO5       = 0;   // SET INPUT TO HIGH

Regards,

Kuldeep

over 14 years ago

0 Brett Larimore over 14 years ago

TI__Guru 57255 points

Kuldeep,

The main issue that I see with your code is that:
GpioCtrlRegs.GPACLEAR.bit.GPIO0 = 0;
does nothing to the GPIO. If instead you do:
GpioCtrlRegs.GPACLEAR.bit.GPIO0 = 1;
GPIO0 will become low.

In general, to change the output of a GPIO, you only need the GPxCLEAR, GPxSET, or GPxDAT instruction. The GPIO control registers only need to be edited during initialization (or whenever you want the basic functionality of a pin to change (ie GPIOoutput to PWM output) )

Thank you,
Brett

C2000™︎ microcontrollers

C2000 microcontrollers forum

Enable and Disable GPIO's in 28335