本帖最后由 xyz549040622 于 2019-12-21 23:20 编辑
- // MSP430G2xx3 Demo - USCI_B0 I2C Master Interface to DAC8571, Write
- //
- // Description: Using UCB0TXIE, a continuous sine wave is output to the
- // external DAC using a 16-point look-up table. Only one start condition
- // is executed. Data is handled by the ISR and the CPU is normally in LPM0.
- // ACLK = n/a, MCLK = SMCLK = BRCLK = default DCO = ~1.2MHz
- //
- // MSP430G2xx3 DAC8571
- // ------------------ ------------
- // -|XIN P1.7/UCB0SDA|<--------------->|SDA |
- // | P1.6/UCB0SCL|---------------->|SCL I2C |
- // -|XOUT | | SLAVE |
- // | I2C MASTER | GND|A0 |
- //
- //
- // DAC8571 I2C address = 0x4C (A0 = GND)
- //
- // D. Dang
- // Texas Instruments Inc.
- // February 2011
- // Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
- //******************************************************************************
- #include <msp430.h>
- const unsigned char Sine_Tab[] = // 16 Point 16-bit Sine Table
- {
- 0xFF, // MSB Word 0
- 0xFF, // LSB
- 0xF6, // MSB Word 1
- 0x40, // LSB
- 0xDA, // MSB Word 2
- 0x81, // LSB
- 0xB0, // MSB Word 3
- 0xFA, // LSB
- 0x7F, // MSB Word 4
- 0xFF, // LSB
- 0x4F, // MSB Word 5
- 0x03, // LSB
- 0x25, // MSB Word 6
- 0x7C, // LSB
- 0x09, // MSB Word 7
- 0xBD, // LSB
- 0x00, // MSB Word 8
- 0x00, // LSB
- 0x09, // MSB Word 9
- 0xBD, // LSB
- 0x25, // MSB Word 10
- 0x7C, // LSB
- 0x4F, // MSB Word 11
- 0x03, // LSB
- 0x7F, // MSB Word 12
- 0xFE, // LSB
- 0xB0, // MSB Word 13
- 0xFA, // LSB
- 0xDA, // MSB Word 14
- 0x81, // LSB
- 0xF6, // MSB Word 15
- 0x40 // LSB
- };
- int main(void)
- {
- WDTCTL = WDTPW + WDTHOLD; // Stop Watchdog Timer
- P1SEL |= BIT6 + BIT7; // Assign I2C pins to USCI_B0
- P1SEL2|= BIT6 + BIT7; // Assign I2C pins to USCI_B0
- UCB0CTL1 |= UCSWRST; // Enable SW reset
- UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC; // I2C Master, synchronous mode
- UCB0CTL1 = UCSSEL_2 + UCSWRST; // Use SMCLK, keep SW reset
- UCB0BR0 = 12; // fSCL = SMCLK/12 = ~100kHz
- UCB0BR1 = 0;
- UCB0I2CSA = 0x4c; // Set slave address
- UCB0CTL1 &= ~UCSWRST; // Clear SW reset, resume operation
- IE2 |= UCB0TXIE; // Enable TX ready interrupt
- UCB0CTL1 |= UCTR + UCTXSTT; // I2C TX, start condition
- UCB0TXBUF = 0x010; // Write DAC control byte
- __bis_SR_register(CPUOFF + GIE); // Enter LPM0 w/ interrupts
- }
- // USCI_B0 Data ISR
- #pragma vector = USCIAB0TX_VECTOR
- __interrupt void USCIAB0TX_ISR(void)
- {
- static unsigned char ByteCtr;
- UCB0TXBUF = Sine_Tab[ByteCtr++]; // Transmit data byte
- ByteCtr &= 0x1f; // Do not exceed table
- }
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