Using SPI onMSP430G2231

what does this do? USICTL1 |= USIIE;
Try to leave it out.

As you only sending byte(s); preferable to use USISRL

And try to wait for while( IFG flag) instead

waitspi bit.b #USIIFG,USICTL1 ; wait until done.
jz waitspi

Hi!

Could you please post your complete code? Sometimes the initializations are located at wrong positions in the code. And as Tony already said, enabling the interrupts isn't a good idea if there is no ISR for it. But this is not visible from your code snippets. Is the GIE also set? Not visible, too. So please provide more of your code.

Dennis

Thank for the fast replies,

I didn't post all the code because I splited the code in several functions, I did a minimalist version to test only 2 SPI transfert. 

This is still the same problem even without seting the ISR:

#include <msp430.h> 

#define	CSN_NRF		(0x0002)

#define CSN_LOW()		P1OUT ^= CSN_NRF
#define CSN_HIGH()		P1OUT |= CSN_NRF

int main(void) {
    WDTCTL = WDTPW | WDTHOLD;	// Stop watchdog timer

    BCSCTL1 = CALBC1_1MHZ;
    DCOCTL = CALDCO_1MHZ;
    BCSCTL2 &= ~(DIVS_3);

    P1DIR |= CSN_NRF;	//en sortie
    CSN_HIGH();

//init SPI
    USICTL0 |= USIPE5 + USIPE6 + USIPE7 + USIMST + USIOE;  // 3-pin, 8-bit SPI master
	USICKCTL = USIDIV_2 + USISSEL_2;
	USICTL0 &= ~USISWRST;                 // USI released for operation

//send on SPI
//once
	CSN_LOW();
	USISRL = 0xAA;			//write data to send
	USICNT = 0x08;				//init the counter to shift data
	while(USICNT != 0 );
	CSN_HIGH();

//twince
	CSN_LOW();
	USISRL = 0x55;			//write data to send
	USICNT = 0x08;				//init the counter to shift data
	while(USICNT != 0 );

	CSN_HIGH();
	while(1);

}

This is the capture of 2 transferts:

I don't understand why the number of SCK is not 8 for each transfert!

change while(USICNT != 0 ) TO while(!(USICTL1&USIIFG));

When USIIFG = 0 and USICNTx > 0, clock generation is enabled and the master will begin clocking out/in data

This

#define CSN_LOW()   P1OUT ^= CSN_NRF

is not right for setting the output low. It toggles the output. If it was '0' it becomes '1' and vice versa. For setting the output low, write

#define CSN_LOW()   P1OUT &= ~CSN_NRF