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I have to measure distance between an object by ARM1176JZF-S(DS- 5 TOOLS) using ultrasonic sensor. I am not being able to write the codes. I have connected the ultrasonic sensor in the GPIO pins PL061 peripheral bock (j39). Please help me write the codes.
Header file and sample program of ultrasonic distance measuring sensor for mbed is given in HCSR04 - a mercurial repository | mbed and another of ATMega 16 http://www.robokits.co.in/documentation/Ultrasonic%20distance%20sensor.pdf
( #include "hcsr04.h" HCSR04::HCSR04(PinName TrigPin,PinName EchoPin): trigger(TrigPin), echo(EchoPin) { pulsetime.stop(); pulsetime.reset(); echo.rise(this,&HCSR04::isr_rise); echo.fall(this,&HCSR04::isr_fall); trigger=0; } HCSR04::~HCSR04() { } void HCSR04::isr_rise(void) { pulsetime.start(); } void HCSR04::start(void) { trigger=1; wait_us(10); trigger=0; } void HCSR04::isr_fall(void) { pulsetime.stop(); pulsedur = pulsetime.read_us(); distance= (pulsedur*343)/20000; pulsetime.reset(); } void HCSR04::rise (void (*fptr)(void)) { echo.rise(fptr); } void HCSR04::fall (void (*fptr)(void)) { echo.fall(fptr); } unsigned int HCSR04::get_dist_cm() { return distance; } unsigned int HCSR04::get_pulse_us() { return pulsedur; } Here is a sample code usage ********************************************************* #include "hcsr04.h" HCSR04 usensor(p25,p6); int main() { unsigned char count=0; while(1) { usensor.start(); wait_ms(500); dist=usensor.get_dist_cm(); lcd.cls(); lcd.locate(0,0); lcd.printf("cm:%ld",dist ); count++; lcd.locate(0,1); lcd.printf("Distance =%d",count); } } )
http://www.robokits.co.in/documentation/Ultrasonic%20distance%20sensor.pdf
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Sample Program for ATMega16Connections:VCC - +5VDCTrig – PA.6 on ATmega16Echo – PA.7 on ATMega16GND – GNDATMega16 running at 16Mhz
char timer0counter; void main() { char buffer[10]; float range; sei(); //Enable global interrupt sbi(DDRA,6); //Set pin as output cbi(DDRA,7); //Set pin as input while(1) { sbi(PORTA,6); //Send Trigger DELAYUS(10); cbi(PORTA,6); //Send trigger http://www.robokits.co.in http://www.robokitsworld.com Page 4 Ultrasonic Distance Measurement Sensor 4M [RKI-1540] timer0counter=0; TCNT0=0; //Clear timer while(bit_is_clear(PINA,7)); //Wait for rising edge sbi(TCCR0,CS02); //Select prescalar 256 sbi(TIMSK,TOIE0); //Enable timer0 overflow interrupt LCD_CLRSCR(); while(bit_is_set(PINA,7) && timer0counter<9) //wait for falling edge of echo { DELAYUS(5); } cbi(TCCR0,CS02); //Stop timer cbi(TIMSK,TOIE0); if(bit_is_set(PINA,7)) { LCD_PRINT("No OBSTACLE"); } else { range=(256*timer0counter+TCNT0)*16*0.017; //range conversion itoa(range,buffer,10); LCD_PRINT(buffer); UART_PRINT(buffer); UART_PRINT("\n\r"); } DELAYMS(100); } } SIGNAL(SIG_OVERFLOW0) { cbi(TIMSK,TOIE0); TCNT0=0; timer0counter++; UART_PUTCHAR(timer0counter); sbi(TIMSK,TOIE0); if(timer0counter>8) { cbi(TCCR0,CS02); cbi(TIMSK,TOIE0}} )
Hi Albert,
You will need to read the manual for the PL061 peripheral itself to work out how to drive the register interface correctly - it is not a simple as just writing to the base address. You're currently just writing to the base address of a multi-register interface, but the address masking functionality of the peripheral means that this doesn't actually write any GPIO lines.
TRM for PL061:
In software mode (i.e. programming through the register interface), bits [9:2] of the address form an 8-bit mask, and only data values which are not masked take effect. In your case:
0x1010A000=1;
Bits [9:2] are all zero so nothing takes effect. (FWIW you are missing a * "points to operator, but I assume this is just a typo as the compiler would error otherwise).
I _think_ the code below should clear all the GPIO pins (x3FC = an 8-bit mask of xFF), wait for that to complete, and then set GPIO[0] (x004 = an 8-bit mask of 0x01) to 1.
*0x1010A3FC=0; dmb(); *0x1010A004=1;
Note that the data value you write is also an 8-bit on/off mask, not a binary on off for the bit you have selected. If you want to set GPIO[1] to 1 you would need.
*0x1010A008=2;
I'm not 100% sure this works - I don't have access to one of these boards, so just going by the manual. P.S. you may need to mark up the pointers as volatile, or there is a risk the compiler optimizes them out.
*((volatile unsigned int*)0x1010A008)=2;
HTH,
Pete
Sir, its not working. There is no change in the GPIO pins. I have tried just like you have instructed and also done some other experiments. I , here, provide the screen shots of those.
Hi albert,
Try to pick some example projects from the provided code and start with changing few lines of codes and get familiar to it.
The main problem is that I do not have any example project. I tried some experiments, I am not being able to change/modify the GPIO pins.