Why serial communication is needed in Embedded C - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to send a byte over serial communication.

Embedded C

void sendByte(unsigned char data) {
    while(![1]); // Wait until transmit buffer is empty
    TXREG = data;
}

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ARXIF

BRCIF

CTXIE

DTXIF

Attempts:

3 left

💡 Hint

Common Mistakes

Using RXIF which is for receive buffer, not transmit.

The TXIF flag indicates the transmit buffer is empty and ready to send data.

2fill in blank

medium

Complete the code to initialize serial communication at 9600 baud rate.

Embedded C

void initSerial() {
    SPBRG = [1]; // Set baud rate generator
    TXSTA = 0x24; // Enable transmitter, BRGH=1
    RCSTA = 0x90; // Enable serial port and continuous receive
}

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A25

B12

C51

D34

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong SPBRG value causing incorrect baud rate.

For 9600 baud with 4MHz clock and BRGH=1, SPBRG is set to 25.

3fill in blank

hard

Fix the error in the code to correctly receive a byte over serial communication.

Embedded C

unsigned char receiveByte() {
    while(![1]); // Wait until data is received
    return RCREG;
}

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ATXIF

BTXIE

CRCIF

DRCIE

Attempts:

3 left

💡 Hint

Common Mistakes

Using TXIF which is for transmit, not receive.

RCIF flag indicates that a byte has been received and is ready to read.

4fill in blank

hard

Complete the code to handle overrun error when receiving a byte over serial communication.

Embedded C

unsigned char safeReceive() {
    if([1]) {
        [2] = 0;
        [2] = 1;
    }
    while(!RCIF);
    return RCREG;
}

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AOERR

BCREN

CFERR

DTXEN

Attempts:

3 left

💡 Hint

Common Mistakes

Using FERR, which is cleared by reading RCREG, not by toggling CREN.

Not handling OERR properly.

The OERR (overrun error) flag must be cleared by momentarily disabling continuous receive enable (CREN).

5fill in blank

hard

Complete the code to enable transmit interrupt for serial communication.

Embedded C

void enableTXInt() {
    INTCONbits.[1] = 1;
    INTCONbits.[2] = 1;
    PIE1bits.[3] = 1;
}

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AGIE

BPEIE

CTXIE

DRCIE

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting GIE or PEIE, required for any interrupts.

INTCONbits.GIE (global), INTCONbits.PEIE (peripheral), and PIE1bits.TXIE (TX specific) must all be set.