Table of Contents
Overview
This article will teach you all the steps required by a beginner to interface a Push Button with TMS320F28335. In this article, you will learn how to make a pin input in TMS320F28335 and how to read a Digital pin in TMS320F28335. Things you should have before continuing.
SOFTWARE:
Code Composer Studio
HARDWARE REQUIRED:
- DSP controller board (TMS320F28335)
- JTAG, XDS100V2 board
Specifications:
TMS320F28335 Microcontrollers
On-chip memory
- 256K × 16 Flash, 34K × 16 SARAM
- Clock frequency: Up to 150 MHz (6.67-ns cycle time)
- Operating voltage: 1.9-V/1.8-V core, 3.3-V I/O design
- Six-channel DMA controller (for ADC, McBSP, ePWM, XINTF, and SARAM)
Communications peripherals
- Up to 2 CAN modules
- Up to 3 SCI (UART) modules
- Up to 2 McBSP modules (configurable as SPI)
- One SPI module
- One Inter-Integrated Circuit (I2C) bus
Analog subsystem
- 12-bit ADC, 16 channels
- 80-ns conversion rate
- 2 × 8 channel input multiplexer
- Two sample-and-hold
- Single/simultaneous conversions
- Internal or external reference
Enhanced control peripherals (EPWM)
- Up to 18 PWM outputs
- Up to 6 HRPWM outputs with 150-ps MEP resolution
•16-bit or 32-bit External Interface (XINTF)
- GPIO0 to GPIO63 pins can be connected to one of the eight external core interrupts
- –Up to 18 PWM outputs
- –Up to 6 HRPWM outputs with 150-ps MEP
Up to 88 individually programmable, multiplexed GPIO pins with input filtering
Three 32-bit CPU timers
Schematic Diagram
Gpio Connection
| S.No | Gpio_connection | Dsp_connection |
| 1. | Gpio_01( output) | Gpio_01( output) |
| 2. | Gpio_02( output) | Gpio_02( output) |
| 3. | Gpio_03( output) | Gpio_03( output) |
| 4. | Gpio_04( input) | Gpio_04( input) |
| 5. | Gpio_05( input) | Gpio_05( input) |
| 6. | Gpio_06( input) | Gpio_06( input) |
Block diagram:
Step by step execution process:
- Step 1: Initialise the Gpio pin(select the pin number).
- Step 2: Select the pin as output(means 1) or input(means 0).
- Step 3: Repeat steps 1 and 2 for selecting multiple pins.
- Step 4:Select the button GPIO pin as an input pin and give a command for button status
- Step 5: Use the “if” and “else” statements to control the output (ON and OFF ) states
- Step 6:If the button is pressed (ON ) set the CLEAR command to turn On the output
- Step 7: If the button is not pressed then the SET command to stable
- Step 8: Now execute the final code and verify the output.
Final Code
#include "DSP28x_Project.h" //Device headerfile*
#define __TRUE 1
#define __FALSE 0
int button_status1,button_status2,button_status3;
void main(void)
{
InitSysCtrl();
// gpio configuration
EALLOW;
// OUTPUT
GpioCtrlRegs.GPAMUX1.bit.GPIO1 =0; // selecting the gpio pin
GpioCtrlRegs.GPADIR.bit.GPIO1 =1; //1 mean output pin,0 mean input pin
GpioCtrlRegs.GPAPUD.bit.GPIO1 =0; // 0 PULL UP ENABLED 1 PULL UP DISABLE
GpioCtrlRegs.GPAMUX1.bit.GPIO2 =0;// selecting the gpio pin
GpioCtrlRegs.GPADIR.bit.GPIO2 =1;//1 mean output pin,0 mean input pin
GpioCtrlRegs.GPAPUD.bit.GPIO2 =0;// 0 PULL UP ENABLED 1 PULL UP DISABLE
GpioCtrlRegs.GPAMUX1.bit.GPIO3 =0;// selecting the gpio pin
GpioCtrlRegs.GPADIR.bit.GPIO3 =1;//1 mean output pin,0 mean input pin
GpioCtrlRegs.GPAPUD.bit.GPIO3 =0;// 0 PULL UP ENABLED 1 PULL UP DISABLE
// input pin selection
GpioCtrlRegs.GPAMUX1.bit.GPIO4 =0;// selecting the gpio pin
GpioCtrlRegs.GPADIR.bit.GPIO4 =0;//1 mean output pin,0 mean input pin
GpioCtrlRegs.GPAPUD.bit.GPIO4 =0;// 0 PULL UP ENABLED 1 PULL UP DISABLE
GpioCtrlRegs.GPAMUX1.bit.GPIO5 =0;// selecting the gpio pin
GpioCtrlRegs.GPADIR.bit.GPIO5 =0;//1 mean output pin,0 mean input pin
GpioCtrlRegs.GPAPUD.bit.GPIO5 =0;// 0 PULL UP ENABLED 1 PULL UP DISABLE
GpioCtrlRegs.GPAMUX1.bit.GPIO6 =0;// selecting the gpio pin
GpioCtrlRegs.GPADIR.bit.GPIO6 =0;//1 mean output pin,0 mean input pin
GpioCtrlRegs.GPAPUD.bit.GPIO6 =0;// 0 PULL UP ENABLED 1 PULL UP DISABLE
EDIS;
while(1)
{
// here read input data when you press the button read the button status
// when you press the button check the status
// if button status == 0 then turn of the led
// else button status == 1 then turn on the led
button_status1 = GpioDataRegs.GPADAT.bit.GPIO4;
button_status2 = GpioDataRegs.GPADAT.bit.GPIO5;
button_status3 = GpioDataRegs.GPADAT.bit.GPIO6;
if(button_status1 == __FALSE)
{
GpioDataRegs.GPASET.bit.GPIO1=1;
}
else
{
GpioDataRegs.GPACLEAR.bit.GPIO1=1;
}
if(button_status2 == __FALSE)
{
GpioDataRegs.GPACLEAR.bit.GPIO2=1;
}
else
{
GpioDataRegs.GPASET.bit.GPIO2=1;
}
if(button_status3 == __FALSE)
{
GpioDataRegs.GPACLEAR.bit.GPIO3=1;
}
else
{
GpioDataRegs.GPASET.bit.GPIO3=1;
}
}
}
