Question

How many bits are shifted out if the value in USICNT is 7 (SPI communication,USI in MSP43012013)? 7. [10] Ans: 8. Following code section is used whenever we want to send something out of UART. Ca you please write in a sentence the significance of while loop [10] while(!(IFG2 & UCAOTXIFG)): Ans: 9. Suppose you have a character array ch as follows: char chi]- "I am a good person"; Write a section of a code (perhaps a loop) so that all the characters in the array above is sent through UART. Consider all the configurations for setting up UART communication (baud rate, pin selection etc) is already in place. 120]

Answer 1

7. Data is changed on the first SCLK edge and captured on the following edge.  Send data 8 byte

8.

The below function can be used to transmit data through the UART module:

//**Function to send one byte of date to UART**//
void UART_send_char(char bt)  
{
    while(!TXIF);  // hold the program till TX buffer is free
    TXREG = bt; //Load the transmitter buffer with the received value
}
//_____________End of function________________//

Once the module is initialized whatever value is loaded into the register TXREG will be transmitted through UART, but transmission might overlap. Hence we should always check for the Transmission Interrupt flag TXIF. Only if this bit is low we can proceed with the next bit for transmission else we should wait for this flag to get low.

However, above function can be used only to send only one byte of data, to send a complete a stringthe below function should be used

//**Function to convert string to byte**//
void UART_send_string(char* st_pt)
{
    while(*st_pt) //if there is a char
        UART_send_char(*st_pt++); //process it as a byte data
}
//___________End of function______________//

This function might be a bit tricky to understand since it has pointers, but trust me pointers are wonderful and they make programming more easy and this is one good example of the same.

As you can notice we have again called the UART_send_char() but now inside the while loop. We have split the string into individual characters, each time this function is called, one char will be sent to the TXREG and it will get transmitted.