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read and play notes from serial

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Vineet K 2024-04-21 17:22:43 -04:00 committed by Shokara Kou
parent d129c76966
commit 21992cfc54
1 changed files with 32 additions and 14 deletions
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46
notes.c
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@ -38,12 +38,12 @@ unsigned short freqs[] = {
FREQ(1750),
FREQ(2000),
[255] = 0 // used as a 'silent' note
[32] = 0 // used as a 'silent' note
};
unsigned char note = 0;
// 0 = buttons write note+cycles+\xff to UART
// 1 = buttons don't do anything, speaker reads note+cycles+\xff from UART
unsigned char mode = 0;
unsigned char mode = '0';
ISR (PCINT0_vect)
{
@ -82,7 +82,7 @@ void
usart_init(void)
{
// 115200 bps, RX/TX enabled
UBRR0 = 8;
UBRR0 = 103;
UCSR0B = (1 << RXEN0) | (1 << TXEN0);
UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
}
@ -94,6 +94,13 @@ usart_send(unsigned char c)
UDR0 = c;
}
void
usart_send_str(const char *c)
{
for (unsigned char i = 0; c[i] != '\0'; i++)
usart_send(c[i]);
}
unsigned char
usart_read(void)
{
@ -125,9 +132,14 @@ main(void)
// Sends Square wave to the Speaker When a Button is Pressed
unsigned short cycles = 0;
unsigned char tmp = 0;
for (;;) {
for (unsigned char n = 0;; n = (n + 1) % 2) {
if (UCSR0A & (1 << RXC0)) {
mode = UDR0;
PORTD &= ~(1 << P_SPKR);
usart_send(mode);
}
// check if any buttons are pressed, otherwise don't play a note
if (((PINB & PCMSK0) | (PINC & PCMSK1) | (PIND & PCMSK2)) == 0) {
if (mode != '1' && ((PINB & PCMSK0) | (PINC & PCMSK1) | (PIND & PCMSK2)) == 0) {
// if a button was released, then send note and cycles played
if (cycles > 0) {
usart_send(tmp);
@ -135,16 +147,11 @@ main(void)
usart_send(LOW(cycles));
usart_send(0xff);
cycles = 0;
} else {
if (UCSR0A & (1 << RXC0)) {
mode = UDR0;
usart_send(mode);
}
}
continue;
}
if (mode == 0) {
if (mode == '0') {
// Prepare Timer/Counter
TCNT1 = 1;
tmp = note;
@ -159,15 +166,26 @@ main(void)
TIFR1 |= 1 << OCF1A;
TCCR1B &= ~(1 << CS11);
cycles = (cycles + 1) % 0xffff;
} else if (mode == 0xb0) {
} else if (mode == '1') {
note = usart_read();
if (note >= '0') note -= '0';
tmp = usart_read();
cycles = tmp << 8;
tmp = usart_read();
cycles |= tmp;
(void)usart_read();
tmp = usart_read();
// reset to default mode when an invalid note is read
if (tmp != 'z' || note > '@') {
mode = '0';
continue;
}
for (unsigned short i = 0; i < cycles; i++) {
usart_send(HIGH(cycles));
usart_send(LOW(cycles));
usart_send(0);
for (unsigned char i = 0; i < cycles; i++) {
TCNT1 = 1;
OCR1A = freqs[note];
TCCR1B |= 1 << CS11;