MSP432 GPIO Output Voltage Too Low - gpio

Question

I'm an undergraduate student. We have an assignment to use Energia and the MSP432-P401R microcontroller to create an OR gate and AND gate IC tester.
You place the IC in the tester circuit and the tester will first determine if the IC is an AND or OR IC. Then, it will indicate which gates on the chip are functioning properly.
My issue is regrading the logical HIGH output voltage of the MSP432. My input signals, a and b, are passed to the IC gates. When my "a" signal is logical HIGH, its voltage is 2.8V. When my "b" signal is logical HIGH, its voltage is 0.7V. This 0.7V is too low for my ICs to register as a HIGH input. I am reading the voltage directly from the MSP432 pin.
I have tried using different GPIO pins and resetting the board. However, the "b" signal is still 0.7V.
My code for setting up "a" and "b" are similar, so I'm not sure why they are outputting different voltages.
My code:
//IC TEST
//Gate inputs pin assignment
int APin=11;
int BPin=8; //other pins tried: 12, 18, 5
//Gate output read pins
int output1Pin=38;
int output2Pin=37;
int output3Pin=36;
int output4Pin=35;
//LED pins
int gate1LEDPin=31;
int gate2LEDPin=32;
int gate3LEDPin=33;
int gate4LEDPin=34; //Gate functioning indicators
int orLEDPin = 40;
int andLEDPin= 39; //Logic of IC indicators
//Truth Table Arrays with inputs a and b
int aValue[]={0, 0, 1, 1};
int bValue[]={0, 1, 0, 1};
int orTrue[]={0, 1, 1, 1};
int andTrue[]={0, 0, 0, 1};
//Function Declaration
int workTest(int,int); //checks if gate is working
//by comparing gate output to
//expected truth result
int logicTest(); //Returns 0 for OR IC, 1 for AND IC
//Progrram variables
int i; //for loop counter
int gate1Result;
int gate2Result;
int gate3Result;
int gate4Result; //Stores number of times gate outputs
//correct value for each ab input
int logicRead; //0 is OR gate. 1 is AND gate
//--------------SETUP-----------------
void setup()
{
Serial.begin(9600);
pinMode(APin, OUTPUT);
pinMode(BPin, OUTPUT);
pinMode(output1Pin, INPUT);
pinMode(output2Pin, INPUT);
pinMode(output3Pin, INPUT);
pinMode(output4Pin, INPUT); //gate output reads
pinMode(orLEDPin, OUTPUT);
pinMode(andLEDPin, OUTPUT);
pinMode(gate1LEDPin, OUTPUT);
pinMode(gate2LEDPin, OUTPUT);
pinMode(gate3LEDPin, OUTPUT);
pinMode(gate4LEDPin, OUTPUT);
}
//END SETUP
//-----------------LOOP---------------------
void loop()
{
gate1Result = 0;
gate2Result = 0;
gate3Result = 0;
gate4Result = 0;
//test IC for its logic function
logicRead = logicTest(); //logicTest returns 0 for OR, 1 for AND
if(logicRead == 9) //logic of IC cannot be determined
{
Serial.println("Try again");
}
if(logicRead != 9)
{
for(i=0; i<4; i++)
{
digitalWrite(APin, aValue[i]); //Load ith value of aValue array
digitalWrite(BPin, bValue[i]); //Load ith value of bValue array
Serial.print("AB = ");
Serial.print(aValue[i]);
Serial.println(bValue[i]);
delay(4000); //Stabilize input signals
if(logicRead == 0) //OR Testing
{
Serial.print("OR Output should be ");
Serial.println(orTrue[i]);
Serial.print("Gate 1: ");
gate1Result = gate1Result + workTest(orTrue[i], output1Pin);
Serial.print("Gate 2: ");
gate2Result = gate2Result + workTest(orTrue[i], output2Pin);
Serial.print("Gate 3: ");
gate3Result = gate3Result + workTest(orTrue[i], output3Pin);
Serial.print("Gate 4: ");
gate4Result = gate4Result + workTest(orTrue[i], output4Pin);
}
if(logicRead == 1) //AND Testing
{
Serial.print("AND Output should be ");
Serial.println(andTrue[i]);
Serial.print("Gate 1: ");
gate1Result = gate1Result + workTest(andTrue[i], output1Pin);
Serial.print("Gate 2: ");
gate2Result = gate2Result + workTest(andTrue[i], output2Pin);
Serial.print("Gate 3: ");
gate3Result = gate3Result + workTest(andTrue[i], output3Pin);
Serial.print("Gate 4: ");
gate4Result = gate4Result + workTest(andTrue[i], output4Pin);
}
}
//Write gate 1 LED
if(gate1Result == 4)
{
digitalWrite(gate1LEDPin, HIGH);
Serial.println("Gate 1 works");
}
else
{
digitalWrite(gate1LEDPin, LOW);
Serial.println("Gate 1 FAIL");
}
//Write gate 2 LED
if(gate2Result == 4)
{
digitalWrite(gate2LEDPin, HIGH);
Serial.println("Gate 2 works");
}
else
{
digitalWrite(gate2LEDPin, LOW);
Serial.println("Gate 2 FAIL");
}
//Write gate 3 LED
if(gate3Result == 4)
{
digitalWrite(gate3LEDPin, HIGH);
Serial.println("Gate 3 works");
}
else
{
digitalWrite(gate3LEDPin, LOW);
Serial.println("Gate 3 FAIL");
}
//Write gate 4 LED
if(gate4Result == 4)
{
digitalWrite(gate4LEDPin, HIGH);
Serial.println("Gate 4 works");
}
else
{
digitalWrite(gate4LEDPin, LOW);
Serial.println("Gate 4 FAIL");
}
}
Serial.println();
Serial.println();
delay(10000); //Wait 10 sec before running code again
}//End void loop
//-----------Function Definitions-----------------------
//This function tests if all gates of the IC are working
//Returns 1 if gate is functioning
//Returns 0 if gate is not functioning
int workTest(int truth, int gateNum)
{
int gateRead = 0; //Updates for each gate output
int result = 0; //TotResult is 1 for all gates pass, 0 for any gate fail
gateRead= digitalRead(gateNum);
if(gateRead == truth)
{
result = 1;
}
else
{
result = 0;
}
Serial.println(gateRead);
return result; //1 for pass, 0 for gate fails
}
//This function tests the logic of the IC
//Returns 1 if IC is an AND gate
//Returns 0 if IC is an OR gate
//Allows for 1 broken gate
//If more than 1 gate broken, logic cannot
//be determined
int logicTest()
{
int aVal[]={0, 1};
int bVal[]={1, 0};
int outputCount = 0;
int logicGate = 0;
int c;
int gate1;
int gate2;
int gate3;
int gate4;
for(c=0; c<2; c++) //only testing ab = 01 and ab = 10
{
digitalWrite(APin, aVal[c]);
digitalWrite(BPin, bVal[c]);
delay(1000); //Stabilize input delay
gate1=digitalRead(output1Pin);
gate2=digitalRead(output2Pin);
gate3=digitalRead(output3Pin);
gate4=digitalRead(output4Pin);
outputCount = outputCount + gate1 + gate2 + gate3 + gate4;
}
if(outputCount < 3) //IC is likely AND gate w/ 1 broken gate
{
logicGate = 1;
Serial.println("IC is an AND gate");
digitalWrite(andLEDPin, HIGH);
digitalWrite(orLEDPin, LOW);
}
else if(outputCount > 5 && outputCount < 9) //IC is likely OR gate w/ 1 broken gate
{
logicGate = 0;
Serial.println("IC is an OR gate");
digitalWrite(andLEDPin, LOW);
digitalWrite(orLEDPin, HIGH);
}
else
{
logicGate = 9;
digitalWrite(andLEDPin, LOW);
digitalWrite(orLEDPin, LOW);
Serial.println("Logic of IC could not be determined");
Serial.println("IC could be broken. Make sure IC is connected properly.");
Serial.println();
}
return logicGate;
}
Here is the circuit setup: