Ein Beispiel-Programm bzw. Beispiel-Initialsierung für USCI (Universial Serial Communication Interface) mit dem MSP430G2553 (im SPI-Mode). Das Programm an sich ist fast identisch mit dem Programm aus “MSP430 USI Initialisierung“. Es werden also wieder Bytes (0-255) an das Schieberegister gesendet.
Schaltplan
C-Programm
- /*************************************************
- * ___ _ _
- * | |_ _ _| |___ ___ _| |___
- * | | |_'_| . | -_| _|_| . | -_|
- * |___|_,_|___|___|___|_|___|___|
- *
- * FILE: main.c
- * Author: declis (xdec.de)
- ************************************************/
- #include <msp430g2553.h>
- #define strobe BIT0 // strobe @ P1.0
- #define data BIT7 // data out @ P1.7
- #define clock BIT5 // CLK out @ P1.5
- #define ms 100
- void main(void)
- {
- unsigned char m_sec=ms;
- WDTCTL=WDTPW+WDTHOLD; // stop WDT
- BCSCTL1=CALBC1_1MHZ; // SMCLK=~1MHz
- DCOCTL=CALDCO_1MHZ;
- P1DIR|=strobe;
- P1OUT&=~strobe;
- // USCI_B0 clock output, USCI_B0 SPI Mode: master out
- P1SEL|=clock+data;
- P1SEL2|=clock+data;
- // USCI in reset state
- UCB0CTL1|=UCSWRST;
- // SPI Master, 8bit data length, LSB first, synchronous mode
- // data captured on first UCLK edge, changed on the following edge
- UCB0CTL0|=UCMST+UCSYNC+UCCKPH;
- // USCI CLK-SRC=SMCLK=~1MHz
- UCB0CTL1|=UCSSEL_2;
- // USCI released for operation
- UCB0CTL1&=~UCSWRST;
- // enable TX interrupt
- IE2|=UCB0TXIE;
- // clear TXIFG
- IFG2&=~UCB0TXIFG;
- _EINT(); // enable interrupts
- while(1)
- {
- while(IFG2&UCB0TXIFG); // TX buffer ready?
- UCB0TXBUF++; // increment TX buffer (0-255)
- while(m_sec--) // wait some time (100ms)
- __delay_cycles(1000);
- m_sec=ms;
- }
- }
- #pragma INTERRUPT (USCI)
- #pragma vector=USCIAB0TX_VECTOR
- void USCI(void)
- {
- // transmission done
- P1OUT|=strobe; // enable strobe register
- P1OUT&=~strobe;
- IFG2&=~UCB0TXIFG; // clear TXIFG
- }
/*************************************************
* ___ _ _
* | |_ _ _| |___ ___ _| |___
* | | |_'_| . | -_| _|_| . | -_|
* |___|_,_|___|___|___|_|___|___|
*
* FILE: main.c
* Author: declis (xdec.de)
************************************************/
#include <msp430g2553.h>
#define strobe BIT0 // strobe @ P1.0
#define data BIT7 // data out @ P1.7
#define clock BIT5 // CLK out @ P1.5
#define ms 100
void main(void)
{
unsigned char m_sec=ms;
WDTCTL=WDTPW+WDTHOLD; // stop WDT
BCSCTL1=CALBC1_1MHZ; // SMCLK=~1MHz
DCOCTL=CALDCO_1MHZ;
P1DIR|=strobe;
P1OUT&=~strobe;
// USCI_B0 clock output, USCI_B0 SPI Mode: master out
P1SEL|=clock+data;
P1SEL2|=clock+data;
// USCI in reset state
UCB0CTL1|=UCSWRST;
// SPI Master, 8bit data length, LSB first, synchronous mode
// data captured on first UCLK edge, changed on the following edge
UCB0CTL0|=UCMST+UCSYNC+UCCKPH;
// USCI CLK-SRC=SMCLK=~1MHz
UCB0CTL1|=UCSSEL_2;
// USCI released for operation
UCB0CTL1&=~UCSWRST;
// enable TX interrupt
IE2|=UCB0TXIE;
// clear TXIFG
IFG2&=~UCB0TXIFG;
_EINT(); // enable interrupts
while(1)
{
while(IFG2&UCB0TXIFG); // TX buffer ready?
UCB0TXBUF++; // increment TX buffer (0-255)
while(m_sec--) // wait some time (100ms)
__delay_cycles(1000);
m_sec=ms;
}
}
#pragma INTERRUPT (USCI)
#pragma vector=USCIAB0TX_VECTOR
void USCI(void)
{
// transmission done
P1OUT|=strobe; // enable strobe register
P1OUT&=~strobe;
IFG2&=~UCB0TXIFG; // clear TXIFG
}