Part Number: MSP430FR5994
I have a simple multiplex set up on a breadboard with 6 switches and 2 transistors (2x3). When one transistor is turned on, I read the pin values from the first half of the sensors, then I turn it off and turn on the other transistor and read the second set of sensors. My problem, I think, has to do with my code. If I step through the debugger (or comment out the 'check_key' function) everything works as it should, but if I let it run then incorrect values are displayed through the serial port.
Here are the results if I step through the debugger or if I comment out the 'check_key' code. The first value is the transistor (0 or 1) and the second number is the register value from P3. It shows correctly with a value of '14', which meant that when transistor #2 (1) was turned on, it read that switch #3 on that transistor read a value of 4.
12:17:06.212 -> 14
12:17:06.212 -> 14
12:17:06.212 -> 14
Here are the results when the code is ran:
09:41:08.195 -> 14
09:41:08.195 -> 14
09:41:08.195 -> 17
09:41:08.195 -> 17
09:41:08.195 -> 17
09:41:08.195 -> 17
09:41:08.195 -> 17
09:41:08.195 -> 14
09:41:08.195 -> 17
09:41:08.195 -> 07
In summary, it shows the correct value a few times, but then it starts reading very erratic numbers. For instance, a '7' would mean that all three sensors on the transistor were turned on. I also get random readings that shows transistor #1 (0) had all 3 sensors turned on (07).
Below is the relevant code:
#include <msp430fr5994.h>
typedef int bool;
#define TRUE 1
#define FALSE 0
char left_hand_output[] = { BIT2, BIT3 };
volatile unsigned int LeftKeysStatus[] = {
0x00,
0x00
};
char left_hand_input[] = { BIT0, BIT1, BIT2 };
unsigned int reg_values = 0;
void SerialPrint(char * tx_data, bool lineReturn); // Outputs string to serial port
void UARTInit_Send(void);
char* Int_to_String(int i, char b[]);
void check_key(int reg, int group, bool on, bool left);
int main(void) {
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
UARTInit_Send();
// Disable the GPIO power-on default high-impedance mode to activate
// previously configured port settings
PM5CTL0 &= ~LOCKLPM5;
P1DIR |= BIT2;// | BIT3; //Set P1.2 and P1.3 as output
P1DIR |= BIT3;
P1OUT &= ~BIT2;// | ~BIT3; //Turn off P1.2 and P1.3 initially
P1OUT &= ~BIT3;
P3DIR &= ~BIT0; // | ~BIT1 | ~BIT2; //Set P3.1, P3.2, P3.3 as INPUT
P3DIR &= ~BIT1;
P3DIR &= ~BIT2;
P3REN |= BIT0 | BIT1 | BIT2; //Enable pullup/down resistors
P3OUT &= ~BIT0 | ~BIT1 | ~BIT2; //Select pullup resistors
while(1) // polling
{
volatile unsigned int i;
for (i=0; i<2;++i){
unsigned int pin = left_hand_output[i];
P1OUT |= pin;
//A slight delay is needed here or else we'll be reading the previous pin
__delay_cycles(300);
reg_values = P3IN;
P1OUT &= ~pin;
//check if something changed
if (reg_values != LeftKeysStatus[i]){
//-----------THIS READS THE CORRECT VALUE--------------
//char indexValue[12];
//Int_to_String(i, indexValue);
//SerialPrint(indexValue, FALSE);
//char dataValue[12];
//Int_to_String(reg_values, dataValue);
//SerialPrint(dataValue, TRUE);
//if the byte value is greater, we're turning the switch on; else, turning it off.
if (reg_values > LeftKeysStatus[i]){
//using bit-wise OR to send modified bits only
check_key(reg_values ^ LeftKeysStatus[i], i, TRUE);
}
else {
check_key(reg_values ^ LeftKeysStatus[i], i, FALSE);
}
}
}
}
}
//Check to see which bits have changed and send the appropriate midi message
void check_key(int reg, int group, bool on){
//-----------THIS READS THE WRONG VALUE--------------
char indexValue[12];
Int_to_String(group, indexValue);
SerialPrint(indexValue, FALSE);
char dataValue[12];
Int_to_String(reg, dataValue);
SerialPrint(dataValue, TRUE);
}
Any help on what is going on would be appreciated.
