Hello everyone,
I am trying to use camera module OV7670 with Arduino mega (ATmega 2560) and transmit the image through Bluetooth module HC-05 to mobile application. I have done the same project with the Arduino UNO and it is successful.
First I tried to see whether I am able to transmit the image through USB connection to PC and read the image through a frame grabber software. For this purpose I used the code from the following thread:
https://forum.arduino.cc/t/solved-problem-with-camera-module-ov7670/514763/6
and the code is posted below.
// Pins configurations:
// SDA/SIOD ---> pin A4 (for Arduino UNO) | pin 20/SDA (for Arduino MEGA)
// SCL/SIOC ---> pin A5 (for Arduino UNO) | pin 21/SCL (for Arduino MEGA)
// MCLK/XCLK --> pin 11 (for Arduino UNO) | pin 10 (for Arduino MEGA)
// PCLK -------> pin 2
// VS/VSYNC ---> pin 3
// HS/HREF ----> pin 8
// D0 ---------> pin A0
// D1 ---------> pin A1
// D2 ---------> pin A2
// D3 ---------> pin A3
// D4 ---------> pin 4
// D5 ---------> pin 5
// D6 ---------> pin 6
// D7 ---------> pin 7
#include <Wire.h>
#define CAMERA_ADDRESS 0x21
// Definitions of functions for manipulating the Arduino boards pins according to each Arduino board registers, so the code will work for both Arduino UNO and Arduino MEGA:
// The only change is the connections of the SDA/SIOD, SCL/SIOC and MCLK/XCLK pins to each board (see the pins configurations above).
#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) // If you are using Arduino MEGA the IDE will automatically define the "__AVR_ATmega1280__" or "__AVR_ATmega2560__" constants.
#define TIMER2_PWM_A_PIN_MODE_OUTPUT() ({ DDRB |= 0b00010000; })
#define PIN2_DIGITAL_READ() ({ (PINE & 0b00010000) == 0 ? LOW : HIGH; })
#define PIN3_DIGITAL_READ() ({ (PINE & 0b00100000) == 0 ? LOW : HIGH; })
#define PIN4_DIGITAL_READ() ({ (PING & 0b00100000) == 0 ? LOW : HIGH; })
#define PIN5_DIGITAL_READ() ({ (PINE & 0b00001000) == 0 ? LOW : HIGH; })
#define PIN6_DIGITAL_READ() ({ (PINH & 0b00001000) == 0 ? LOW : HIGH; })
#define PIN7_DIGITAL_READ() ({ (PINH & 0b00010000) == 0 ? LOW : HIGH; })
#define PIN8_DIGITAL_READ() ({ (PINH & 0b00100000) == 0 ? LOW : HIGH; })
#define PINA0_DIGITAL_READ() ({ (PINF & 0b00000001) == 0 ? LOW : HIGH; })
#define PINA1_DIGITAL_READ() ({ (PINF & 0b00000010) == 0 ? LOW : HIGH; })
#define PINA2_DIGITAL_READ() ({ (PINF & 0b00000100) == 0 ? LOW : HIGH; })
#define PINA3_DIGITAL_READ() ({ (PINF & 0b00001000) == 0 ? LOW : HIGH; })
#elif defined(__AVR_ATmega328P__) // If you are using Arduino UNO the IDE will automatically define the "__AVR_ATmega328P__" constant.
#define TIMER2_PWM_A_PIN_MODE_OUTPUT() ({ DDRB |= 0b00001000; })
#define PIN2_DIGITAL_READ() ({ (PIND & 0b00000100) == 0 ? LOW : HIGH; })
#define PIN3_DIGITAL_READ() ({ (PIND & 0b00001000) == 0 ? LOW : HIGH; })
#define PIN4_DIGITAL_READ() ({ (PIND & 0b00010000) == 0 ? LOW : HIGH; })
#define PIN5_DIGITAL_READ() ({ (PIND & 0b00100000) == 0 ? LOW : HIGH; })
#define PIN6_DIGITAL_READ() ({ (PIND & 0b01000000) == 0 ? LOW : HIGH; })
#define PIN7_DIGITAL_READ() ({ (PIND & 0b10000000) == 0 ? LOW : HIGH; })
#define PIN8_DIGITAL_READ() ({ (PINB & 0b00000001) == 0 ? LOW : HIGH; })
#define PINA0_DIGITAL_READ() ({ (PINC & 0b00000001) == 0 ? LOW : HIGH; })
#define PINA1_DIGITAL_READ() ({ (PINC & 0b00000010) == 0 ? LOW : HIGH; })
#define PINA2_DIGITAL_READ() ({ (PINC & 0b00000100) == 0 ? LOW : HIGH; })
#define PINA3_DIGITAL_READ() ({ (PINC & 0b00001000) == 0 ? LOW : HIGH; })
#endif
void initializePWMTimer() {
cli();
TIMER2_PWM_A_PIN_MODE_OUTPUT(); // Set the A PWM pin of TIMER2 to output
ASSR &= ~(_BV(EXCLK) | _BV(AS2));
TCCR2A = (1 << COM2A0) | (1 << WGM21) | (1 << WGM20);
TCCR2B = (1 << WGM22) | (1 << CS20);
OCR2A = 0;
sei();
}
byte readCameraRegister(byte registerId) {
Wire.beginTransmission(CAMERA_ADDRESS);
Wire.write(registerId);
Wire.endTransmission();
Wire.requestFrom(CAMERA_ADDRESS, 1);
while (Wire.available() <= 0);
byte registerValue = Wire.read();
delay(1);
return registerValue;
}
void writeCameraRegister(byte registerId, byte registerValue) {
Wire.beginTransmission(CAMERA_ADDRESS);
Wire.write(registerId);
Wire.write(registerValue);
Wire.endTransmission();
delay(1);
}
void captureFrame(unsigned int frameWidth, unsigned int frameHeight) {
Serial.print("*RDY*"); // send to the frame capture software a "start of frame" message for beginning capturing
delay(1000);
cli(); // disable all interrupts during frame capture (because it needs to be as fast as possible)
while (PIN3_DIGITAL_READ() == LOW); // wait until VS/VSYNC pin is high
while (PIN3_DIGITAL_READ() == HIGH); // wait until VS/VSYNC pin is low
unsigned int tempWidth = 0;
while (frameHeight--) {
tempWidth = frameWidth;
while (tempWidth--) {
while (PIN2_DIGITAL_READ() == LOW); // wait until PCLK pin is high
while (PIN2_DIGITAL_READ() == HIGH); // wait until PCLK pin is low
byte byteToWrite = 0b00000000;
byteToWrite |= ((PIN7_DIGITAL_READ() == HIGH) << 7);
byteToWrite |= ((PIN6_DIGITAL_READ() == HIGH) << 6);
byteToWrite |= ((PIN5_DIGITAL_READ() == HIGH) << 5);
byteToWrite |= ((PIN4_DIGITAL_READ() == HIGH) << 4);
byteToWrite |= ((PINA3_DIGITAL_READ() == HIGH) << 3);
byteToWrite |= ((PINA2_DIGITAL_READ() == HIGH) << 2);
byteToWrite |= ((PINA1_DIGITAL_READ() == HIGH) << 1);
byteToWrite |= ((PINA0_DIGITAL_READ() == HIGH));
UDR0 = byteToWrite; // send data via serial connection with UART register (we need to use the serial register directly for fast transfer)
while (PIN2_DIGITAL_READ() == LOW); // wait until PCLK pin is high
while (PIN2_DIGITAL_READ() == HIGH); // wait until PCLK pin is low
// ignore each second byte (for a grayscale image we only need each first byte, which represents luminescence)
}
}
sei(); // enable all interrupts
delay(1000);
}
void setup() {
initializePWMTimer();
Wire.begin();
Serial.begin(1000000); // the frame capture software communicates with the Arduino at a baud rate of 1MHz
}
void loop() {
captureFrame(320, 240); // capture a frame at QVGA resolution (320 x 240)
}
frame grabber software I used was the same software in the following link.
https://github.com/pintushaw/Serialportreader
I used the same code and the frame grabber software with the arduino uno and it is succesful. but with the arduino mega it does not work!! The serialportreader says
the error operation time out
I did little bit is debugging to the code and I realize that the problem is at the following part of the code.
while (PIN2_DIGITAL_READ() == LOW); // wait until PCLK pin is high
while (PIN2_DIGITAL_READ() == HIGH); // wait until PCLK pin is low
It appears that it does not break the while loop. I am not sure whether it is a problem of the board of something wrong with the code. But the same code work with Arduino UNO. I don't know how to set the PCLK for another pin (for example pin 28) so I can know whether it is a problem of the board. Can anyone please help?
Thank you in advance.