// function to initialize UART
void uart_init(uint32_t Desired_Baudrate) {
// If its not already set, calculate the baud rate dynamically,
// based on current microcontroller speed and user specified
// desired baudrate.
#ifndef UBBR
#define UBBR ((F_CPU)/(Desired_Baudrate*8UL)-1)
#endif
// Set to double speed mode.
SS_UCSRnA |= (1 << SS_U2Xn);
// Set baud rate.
SS_UBRRnH = (uint8_t)(UBBR >> 8);
SS_UBRRnL = (uint8_t)UBBR;
// Enable receiver, transmitter, and RxComplete interrupt
SS_UCSRnB = (1 << SS_RXENn) | (1 << SS_TXENn) | (1 << SS_RXCIEn);
// Set frame format: 8data, 1 stop bit
SS_UCSRnC = (1 << SS_USBSn) | (1 << SS_UCSZn0) | (1 << SS_UCSZn1);
// Enable the Global Interrupt Enbl flag to process interrupts
DIGITAL_SET_OUT(SS_UART_TXE); // Set nRX enable and TX enable as outputs
DIGITAL_SET_OUT(SS_UART_nRXE);
DIGITAL_SET_LOW(SS_UART_TXE); // Set nRX enable and TX enable to 0
DIGITAL_SET_LOW(SS_UART_nRXE); // Enable RX and disable TX
DIGITAL_PULLUP_ON(SS_UART_RX);
sei(); // Enable interrupts
}
// Public functions called from main.c
void initDigital() {
DIGITAL_PULLUP_ON(IN0);
DIGITAL_SET_HIGH(IN1);
DIGITAL_SET_LOW(IN2);
DIGITAL_SET_LOW(IN3);
// TODO(tobinsarah): allow configuration as input/output for each relevant pin
DIGITAL_SET_IN(IN0);
DIGITAL_SET_OUT(IN1);
DIGITAL_SET_OUT(IN2);
DIGITAL_SET_OUT(IN3);
}
// Public functions called from main.c
void initBuzzer() {
// Does everything to set up the analog stuffs.
// Turn on pin PC1 (which maps to IN0)
ADMUX |= (1 << MUX3) | (1 << MUX1);
#if F_CPU != 8000000
#error Clock speed not correct
#endif
// Enable the ADC and set the division factor between
// the system clock frequency and the input clock to the ADC.
// Division factor: 111 = 128
ADCSRA |= (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0) | (1 << ADEN);
// Set PA6 pin as output in order to see PWM signal
// Set pulse width to 1/2 of entire duration.
OCR1BL = 0x7F;
DIGITAL_SET_OUT(PWM0);
// DIGITAL_SET is also ANALOG_SET apparently...
DIGITAL_SET_IN(IN1);
DIGITAL_SET_IN(IN2);
DIGITAL_SET_IN(IN3);
// Testing
DIGITAL_SET_OUT(PWM1);
DIGITAL_SET_HIGH(PWM1);
// End Testing
// Set PWM to Fast PWM Mode Operation, with non-inverting PWM
// Clear OC1B on Compare Match
// Clock prescaler = 1/64
TCCR1A = (1 << COM1B1) | (1 << WGM10);
TCCR1B = (1 << WGM12) | (1 << CS11) | (1 << CS10);
// Enable Timer/Counter1 Overflow Interrupt
TIMSK = (1 << TOIE1);
sei();
}