Configuring the MSP430 USCI_A1 UART module

Other Parts Discussed in Thread: MSP430F5529

Hi guys,

I have been developing a UART library for the msp430f5529 which I am testing on my msp430f5529 launchpad.

I have written the code for the USCI_A0 module and it works perfectly. Now I transferred it to the USCI_A1 module.

Basically the code (initialisation and algorithm) is exactly the same but I changed the pinouts, ISR nector name and register names from, for example, UCA0IFG to UCA1IFG (just the number).

When I run the algorithm, the process does go into the ISR, runs properly through all the processes, yet no data can be detected on the pins.

Regarding the launchpad dev board, I connected my logic analyser with the male header's pins TXD and RXD pins next to the SBW RST and SBW TST pins; i checked with the schematic of the board that these are connected with the  pins 4.4 and 4.5 on the msp respectively.

The following is the code I am using:

//This function sets the UART ports and registers
int UART_initialise(char *UART_module){

		P4SEL 	|= RXD_UCA1 + TXD_UCA1 ; // P4.5 = RXD, P4.4=TXD
		P4DIR   |= TXD_UCA1; // set as output
		P4DIR   &= ~RXD_UCA1; // set as input

		UCA1CTL1 |= UCSWRST;                      // **Put state machine in reset**

		//Set UART module
		UCA1CTL0 = UCMODE_0; //set UART mode
		UCA1CTL1 |= UCSSEL_1; // Set ACLK(XT1, 32KHz) as BRCLK
		UCA1BR0 = 0x03;                           // 32kHz/9600=3.41 (see User's Guide)
		UCA1BR1 = 0x00;                           //
		UCA1MCTL = UCBRS_3+UCBRF_0;               // Modulation UCBRSx=3, UCBRFx=0

		UCA1CTL1 &= ~UCSWRST; // **Initialize USCI state machine**

		return 1;

}


//This function transmits string (char array) pointed to by data_to_send
//via UART.
//Transfer is ready when transfer_ready variable is asserted.
int UART_transmit(char *data_to_send,char *UART_module)
{
		UART_transmit_function_UCA1 = 1;

		UCA1IFG &= ~UCTXIFG; //clear flag (just in case)

		UART_transmit_function_ready_UCA1 = 0; //global variable; 1 is transmit is ready
		tx_data_cnt_UCA1 = 0;	//global variable; reset counter
		tx_data_UCA1 = data_to_send; // copy pointer to global varible
		tx_data_size_UCA1 = strlen(tx_data_UCA1); //global variable, calculate size of string to send

		UCA1TXBUF = *(tx_data_UCA1 + tx_data_cnt_UCA1*sizeof(char)); //load UART transmit buffer

		UCA1IE |= UCTXIE;  //Enable TX interrupt

		return 1;
}


ISR:

#pragma vector = USCI_A1_VECTOR
__interrupt void USCIA1RTX_ISR(void){

extern	int UART_transmit_function_UCA1;
extern	int UART_transmit_function_ready_UCA1;
extern	int tx_data_cnt_UCA1;
extern	char *tx_data_UCA1;
extern	int tx_data_size_UCA1;


	if((UCA1IFG & UCTXIFG) != 0){

		   ++tx_data_cnt_UCA1;

		   if(tx_data_cnt_UCA1 <= (tx_data_size_UCA1-1)){
			   UCA1TXBUF = *(tx_data_UCA1 + tx_data_cnt_UCA1*sizeof(char)); //load UART transmit buffer
		   }
		   else {
			   UART_transmit_function_ready_UCA1 = 1;
			   UCA1IE &= ~UCTXIE; // Disable USCI_A0 TX interrupt
			   UCA1IFG &= ~UCTXIFG; //clear flag
			   //__bic_SR_register_on_exit(CPUOFF);      // Exit LPM0
		   }
	
   }
}

I am using the XTl1 oscillator(32Khz)..

Thanks for any help, any suggestion is appreciated.

Thanks for your time.

best regards,

Eman