//******************************************************************************
// 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 | 8
// 8 | /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 <msp430g2221.h>
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) // Loop
{
unsigned i;
for (i = 0xFFFF; i > 0; i--); // Delay
while (!(USIIFG & USICTL1)); // Counter clear?
P1OUT &= ~0x02; // Latch data into 'HC165
P1OUT |= 0x02;
// ******************** // Read data are ready to be written
USICNT = 8; // re-load counter
}
}
SPI程序，仅供参考
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