Information Logging

An easy way to output to a txt file?  It's not going to be that simple with only a UART connection.  Easiest solution would be sending characters over UART to a terminal and then copy/paste or save the terminal log into a text file.  Otherwise you need a GUI/software conversion program to accept the UART characters and write them into a pre-existing text file within a known location.  Sending strings over UART itself without using printf() is not too hard.  For example:

unsigned int i = 0;
const char string[] = {"ADC value: "}; //Strings being sent to the PC
const int size = 10; //String size
const char endlinestring[] = {"\n\r"}; //Command to end line
const int endlinesize = 4;

//Send the string
for(i=0; i<=size; i++)
{
while(!(UCA0IFG&UCTXIFG));
UCA0TXBUF = string[i];
}

//Sends the adc raw value, will have to be converted from ASCII to hex/dec here or on host side for meaningful data
while(!(UCA0IFG&UCTXIFG));
UCA0TXBUF = saved_adc_value;                                  //From ADC12MEMx conversion results

//Start a new line for the next string
for(i=0; i<=endlinesize; i++)
{
while(!(UCA0IFG&UCTXIFG));
UCA0TXBUF = endlinestring[i];
}

Regards,

Ryan

Let's cover our bases so we can figure out what is going on.  These instructions are for a MSP-EXP430F5529LP (F5529 LaunchPad) and will need to be changed depending on the device you are using:

1. Download the MSP430F552x C Examples package and load MSP430F55xx_uscia0_uart_04.c (9600 UART Echo) to your device.

2. Make sure that the RXD and TXD jumpers are correctly installed in the upright position.

3. Confirm that your putty configuration is as shown (with your own COM port setting, of course).  Serial settings should already be correct but check to see that it's in the format of 8 data bits, 1 stop bit, and no parity.

4. Open the COM port and type something into your keyboard.  The terminal should not have local echo turned on, so any characters that appear on the terminal are coming from your MSP430 device.

Once you can confirm that you have communication working with this demo, it should be easier to ramp development of your own application.

Regards,

Ryan

Ryan,

So I have performed this demo before, but I have not received anything from it.  The only thing that you proposed that I had not done earlier was putting the RXD and TXD jumpers in the upright position, thus connecting RXD to TXD (This should have been obvious to me before).  In the code presented, it cycles at the bold code I put up.  It runs through it all and just cycles in LPM.  It picks up noise (accidentally rubbing fingers across created jumbled garbage on terminal output), and when I paused the code to write directly to the TXD buffer, it erases it before resuming.  It there a way I can shove in input and get an output with this demo?  I really appreciate this Ryan.  

#include <msp430.h>

int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P3SEL = BIT3+BIT4; // P3.4,5 = USCI_A0 TXD/RXD
UCA0CTL1 |= UCSWRST; // **Put state machine in reset**
UCA0CTL1 |= UCSSEL_2; // SMCLK
UCA0BR0 = 6; // 1MHz 9600 (see User's Guide)
UCA0BR1 = 0; // 1MHz 9600
UCA0MCTL = UCBRS_0 + UCBRF_13 + UCOS16; // Modln UCBRSx=0, UCBRFx=0,
// over sampling
UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt

__bis_SR_register(LPM0_bits + GIE); // Enter LPM0, interrupts enabled
__no_operation(); // For debugger
}

// Echo back RXed character, confirm TX buffer is ready first
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A0_VECTOR
__interrupt void USCI_A0_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USCI_A0_VECTOR))) USCI_A0_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(UCA0IV,4))
{
case 0:break; // Vector 0 - no interrupt
case 2: // Vector 2 - RXIFG
while (!(UCA0IFG&UCTXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = UCA0RXBUF; // TX -> RXed character
break;
case 4:break; // Vector 4 - TXIFG
default: break;
}
}

Ryan,

So what I have been doing was something learned in class awhile back.  Through the IDE, I was going in and changing the value in the TXD register.  That was not working.  I did what you suggested, but it still cycles on that piece.  How do I trigger the interrupt?  Keyboard presses is not working.  Neither are presses of the buttons on the microcontroller (I just tried it, but I know that the ISR's for the UART are triggered elsewhere.).

Rahim,

This specific interrupt pertains to vector 2 of the USCIA0 ISR, which triggers when the RXIFG flag is set high.  This happens after a value is received from the sender and stored in UCA0RXBUF.

Regards,

Ryan

Ryan,

So what do I need to do to trigger the flag?  I need to send something into the UCA0RXBUFFER?  What steps do I take to perform this action?

As you are using F55xx are you trying to use USB HID to send the data?
Or you are trying to use UART backdoor of a Launchpad?

To send a text string all the data have to be converted in ascii, and you need a receiver program that is getting the data and saving it
Or maybe just copy and paste the screen? terterm is a terminal program that should do it.

Send data with usci is simple, just write a byte to txbuff and away it goes. you get a IRQ when it's ready for a new byte in its buffered register.

USB.  The only thing it is connected is my desktop to my USB to my MSP.