//****************************************************************************** // MSP430G2x21/G2x31 Demo - USI SPI Interface with HC165/164 Shift Registers // // Description: Demonstrate USI in two-way SPI mode Data are read from // an HC165, and same data written back to the HC164 // ACLK = n/a MCLK = SMCLK = default DCO, USICLK = SMCLK/2 // //*USART0 control bits are in different SFR's from other MSP430's// // // MSP430G2x21/G2x31 // // /|\| XIN|// | | | ^ HC164 // HC165 |RST XOUT|| // -| | |-|/CLR,B | // | /LD|< -|P1.1 SIMO0/P1.6| >|A Qx| \-> // -\->|A-H CLK|< -|P1.5/SCLK0 - P1.5| >|CLK | // |-|INH QH| ->|P1.7/SOMI0 | | | // |-|SER | | | | | // - | | | | | | // // D Dang // Texas Instruments Inc // October 2010 // Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10 //****************************************************************************** #include void main(void) { WDTCTL = WDTPW + WDTHOLD; // Stop WDT P1OUT = 0; P1OUT |= 0x02; P1DIR |= 0x02; USICTL0 |= USIPE7 + USIPE6 + USIPE5 + USIMST + USIOE; // Port, SPI Master USICTL1 |= USICKPH + USIIE; // Counter interrupt, flag remains set USICKCTL = USIDIV_1 + USISSEL_2; // /2 SMCLK USICTL0 &= ~USISWRST; // USI released for operation USICNT = 8; // init-load counter while (1) { unsigned i; for (i = 0xFFFF; i > 0; i ); while (!(USIIFG & USICTL1)); P1OUT &= ~0x02; P1OUT |= 0x02; // ******************** USICNT = 8; } } // Loop // Delay // Counter clear? // Latch data into 'HC165 // Read data are ready to be written // re-load counter