MSP430 G2553 Launchpad实现电容测量

// C meter 2015.9.26
//
// P1.5(TA0.0) --[||||]----------- P1.4(CA3)
// R=10kOhm |
// -----
// cap -----
// |
// GND
// http://zlbg.cnblogs.com
///////////////////////////////////////// #include "io430.h" #define LED1 BIT0 // P1.0, red led
#define LED2 BIT6 // P1.6, green led #define VMEAS BIT4 // P1.4(CA4) for voltage measurement of the cap
#define VCTRL BIT5 // P1.5(TA0.0) for voltage control
#define PUSH2 BIT3 // P1.3, button #define RXD BIT1 //P1.1
#define TXD BIT2 //P1.2 #define READY 0
#define CHARGING 1
#define DISCHARGING 2
#define FINISH_DC 3 #define R_SERIES 10000 //10kOhm
#define LN4 1.3863 //functions for C meter
void P1Init(void);
void TA0Init(void);
void CAInit(void);

37 void setReadyStatus(void); //functions for printf()
void sendByte(unsigned char);
void printf(char *, ...);
void initUART(void); char state = READY;
unsigned char overflowsCharging = ;
unsigned char overflowsDischarging = ;
unsigned char i = ;
float capacitance = ; // unit: nF void main(void)
{
// Stop watchdog timer to prevent time out reset
WDTCTL = WDTPW + WDTHOLD; // DCO setup
BCSCTL1 = CALBC1_1MHZ; //running at 1Mhz
DCOCTL = CALDCO_1MHZ; // P1 setup
P1Init(); // Timer0 setup
TA0Init(); // CA setup
CAInit(); // UART setup
initUART(); setReadyStatus(); __enable_interrupt(); // enter LP mode
LPM0; } void P1Init(void)
{
P1OUT = ; // set P1.3 (PUSH2) as input with pullup
P1OUT |= PUSH2;
P1REN |= PUSH2; // set P1.0, P1.6, P1.5 as output
P1DIR |= LED1 + LED2 + VCTRL; // enable P1.3 interrupt
P1IES |= PUSH2; // high -> low transition
P1IFG &= ~PUSH2; // clear the flag
P1IE |= PUSH2;
} void TA0Init(void)
{
// use SMCLK (1MHz), no div, clear, halt
TA0CTL = TASSEL_2 + ID_0 + MC_0 + TACLR; // TA0CCTL0: compare mode, enable interrupt
TA0CCTL0 = CCIE; // TA0CCTL1: capture mode, no capture, CCI1B(CAOUT) input, syn capture
// interrupt enabled
TA0CCTL1 = CCIS_1 + SCS + CAP + CCIE;
} void CAInit(void)
{
//0.25 Vcc ref on V+, halt
CACTL1 = CAREF_1 + CAIES;
// input CA4 (P1.4), remove the jumper) on V-, filter on
CACTL2 = P2CA3 + CAF;
} void setReadyStatus(void)
{
state = READY;
// light led2 and turn off led1 to indicate ready
P1OUT &= ~LED1;
P1OUT |= LED2; //stop and clear timer, stop T0_A1 capture & CA+
TA0CTL = TASSEL_2 + ID_0 + MC_0 + TACLR;
TA0CCTL1 &= ~CM_3;
CACTL1 &= ~CAON; overflowsCharging = ;
} void initUART(void) {
//config P1.1 RXD, P1.2 TXD
P1SEL |= TXD + RXD;
P1SEL2 |= TXD + RXD; //reset UCA0, to be configured
UCA0CTL1 = UCSWRST;
//config
UCA0CTL1 |= UCSSEL_2; //SMCLK
UCA0BR0 = ;
UCA0BR1 = ;//1MHz baut rate = 9600 8-N-1
UCA0MCTL = UCBRS0; // Modulation UCBRSx = 1
//make UCA0 out of reset
UCA0CTL1 &= ~UCSWRST;
} void sendByte(unsigned char byte )
{
while (!(IFG2&UCA0TXIFG)); // USCI_A0 TX buffer ready?
UCA0TXBUF = byte; // TX -> RXed character
} #pragma vector = PORT1_VECTOR
__interrupt void P1_ISR(void)
{
if((P1IFG & PUSH2) == PUSH2)
{
P1IFG &= ~PUSH2; //clear the flag
switch(state)
{
case READY:
state = CHARGING;
// light LED1 and turn off LED2, indicate a busy status
P1OUT |= LED1;
P1OUT &= ~LED2;
//start timer, continuous mode
TACTL |= MC_2;
//start charging
P1OUT |= VCTRL;
break;
default:
break;
} }
else
{
P1IFG = ;
}
} #pragma vector = TIMER0_A0_VECTOR
__interrupt void CCR0_ISR(void)
{
switch(state)
{
case CHARGING:
if (++overflowsCharging == ) // wait 6.5535*50 = 3.28s
{
state = DISCHARGING;
CACTL1 |= CAON; // turn on CA+
TA0CCTL1 |= CM_1; // start TA1 capture on rising edge
P1OUT &= ~VCTRL; // start discharging
overflowsDischarging = ;
}
break;
case DISCHARGING:
overflowsDischarging++;
default:
break; } } #pragma vector = TIMER0_A1_VECTOR
__interrupt void CCR1_ISR(void)
{
TA0CTL &= ~MC_3; //stop timer
TA0CCTL1 &= ~CCIFG; // clear flag
switch(state)
{
case DISCHARGING:
state = FINISH_DC;
capacitance = (overflowsDischarging* + TA0CCR1)* / (R_SERIES*LN4); //nF
//send result to PC
printf("Capatitance: %n", (long unsigned)capacitance);
printf(" nF\r\n"); setReadyStatus();
break;
default:
break;
}
}