Using UART and PC communication to realize ultrasonic distance measurement of msp430g2553 single-chip computer sample _c language

It is suitable for msp430g2553 MCU to use the HC-SR04 ultrasonic ranging module and communicates with PC using UART.

Copy Code code as follows:

#include <msp430.h>
The last time a long current_time;//was measured
/*mypro*/
#define LED_1 BIT0
#define SW_2 BIT3
#define Ta1_1 BIT2//ta0.1 hc-sr04 Echo
#define TRIG BIT4//hc-sr04 TRIG
#define ACCU_GRD 7 Grade "xxx.x" + '//accuracy '
#define MIN_UNIT_TO1M 1000//1 m to 1 mm

/*timer0*/
#define SOUR_CLK 1045000
#define DIV_CLK_1 1
#define SYS_CLK_SIG_1 Sour_clk/div_clk_1
#define DISTANCE 45//DM
#define TIMER_RIG_MAX 0xFFFF
#define Max_time_1 distance*2/34*sys_clk_sig_1
#ifdef Max_time_1
#define SYS_CLK sys_clk_sig_1
#endif
#define UART_TXD BIT2

void Init_timer1 ()
{
P2sel |= ta1_1; TA1.1 cci1b be used
P2dir &= ~ta1_1;
Ta1ctl = Mc_0 + tassel_2; Timera_0 Stop Mode,clock=1mhz
TA1CCTL1 = CCIE + Scci + ccis_1 + SCS + CAP + cm_2; TA0CC1 capture mode + down edge
}
/*uart*/
void Init_uart ()//usci initialization function
{
UCA0CTL1 |= Ucswrst; Initializing serial port Registers
UCA0CTL1 |= ucssel_2; Select Subsystem Clock 1.045MHz
Uca0br0 = 0x6d; Baud rate is 9600
UCA0BR1 = 0x00;
P1sel |= Uart_txd;
P1sel2 |= Uart_txd;
P1dir |= Uart_txd; Set the P1.2 to the second function
UCA0CTL1 &= ~ucswrst; Initialization end
}
Long cal_distance ()//distance calculated by measured time
{
Return (long) ((340* (0.5000*CURRENT_TIME/SYS_CLK) *min_unit_to1m));
}
void delay ()//Rough Latency
{
unsigned char i,j;
for (i=124;i>0;i--)
for (j=8;j>0;j--);
}
Static char * Translater (long distance)//storing the measured distance as a string
{
static Char TRANS[ACCU_GRD];
int i;
Long F;
Trans[0]= ';
if (distance)
for (i=1,f=min_unit_to1m;i<accu_grd-1;i++)//Transformation Core algorithm
{
if (i==4)
{
Trans[i] = '. ';
Continue
}
Trans[i] = ' 0 ' + distance/f;
Distance%= F;
F/= 10;
}
Trans[accu_grd-1] = ' the ';
return trans;
}
void Once_pro ()//Send an ultrasound
{
if (TA1CCTL1 & COV)
TA1CCTL1 &= ~cov;
if (!) ( p1in & BIT3))
{
ta1r = 0;
P1out |= TRIG; Trig US High level

_eint ();
Ta1ctl |= mc_2; Continue mode
P1out &= ~trig;
P1out |= led_1;
while (TA1CCTL1 & CCIFG); Wait for capture interrupt to end
}
Else
{
P1out &= ~led_1;
_dint ();
}
}
void Uart_txstring (char *string)//UART_TX sends a string
{
int i=0;
while (string[i++])
{
switch (i)//filter invalid ' 0 '
{
Case 1:if (string[i]== ' 0 ') continue;
Case 2:if (string[i]== ' 0 ' &&string[i-1]== ' 0 ') continue;
}
Uca0txbuf = String[i];
Delay ();
}
}
/*uart_isr*/
#pragma vector = Usciab0tx_vector
__interrupt void Usci_txdistance ()//send measured distance to PC
{
Uart_txstring ("\n\r");
Uart_txstring ("current");
Uart_txstring ("Distance:");
Uart_txstring (Translater (Cal_distance ()));
Uart_txstring ("cm");
IE2 &= ~uca0txie;
}
/*timer0_int_isr*/
#pragma vector = Timer1_a1_vector
__interrupt void Capture ()
{
Current_time = TA1CCR1;
Ta1ctl &= ~mc_2;
TA1CCTL1 &= ~CCIFG; Clear CC1 interrupt Mark Bit
IE2 |= Uca0txie;
}
/*main*/
void Main ()
{
Wdtctl = Wdtpw + wdthold; Shut the dog.
Dcoctl = 0;
BCSCTL1 = Calbc1_1mhz;
Dcoctl = Caldco_1mhz;
p1out = 0;
p2out = 0;
P1ren |= sw_2;
P2ren |= ta1_1;
P1out |= sw_2;
P1dir &= ~sw_2;
P1dir = TRIG + led_1;
Init_timer1 ();
Init_uart ();
while (1)
{
int c = 8;
while (c--)
Delay ();
if (TA1CCTL1 & CCIFG)
TA1CCTL1 &= ~CCIFG;
Once_pro ();
}
}