sony: Add tone.c

converter/news_usb/tone.c

@@ -0,0 +1,124 @@
+/* 
+  2023 Based on:
+  https://github.com/arduino/ArduinoCore-avr/blob/a7edf4d66f66d42ebb7e166762ac7c11cb299a3f/cores/arduino/Tone.cpp
+
+  A Tone Generator Library
+
+  Written by Brett Hagman
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+#include <avr/interrupt.h>
+
+// Pin for buzzer: PD0
+#define BZ_PIN_PORT     PORTD
+#define BZ_PIN_DDR      DDRD
+#define BZ_PIN_MASK     (1<<0)
+
+volatile long toggle_count;
+
+static void toneBegin(void)
+{
+    // Timer 1
+    //TCCR1A = 0;
+    //TCCR1B = 0;
+
+    // CTC mode
+    //TCCR1B |= WGM12;
+    TCCR1B |= _BV(WGM12);
+    // No prescaling
+    //TCCR1B |= CS10;
+    TCCR1B |= _BV(CS10);
+
+    BZ_PIN_DDR |= BZ_PIN_MASK;
+    BZ_PIN_PORT |= BZ_PIN_MASK;
+}
+
+// frequency (in hertz) and duration (in milliseconds).
+void tone(unsigned int frequency, unsigned long duration)
+{
+    uint8_t prescalarbits = 0b001;
+    uint32_t ocr = 0;
+
+    toneBegin();
+
+    // Set the pinMode as OUTPUT
+    BZ_PIN_DDR |= BZ_PIN_MASK;
+
+    // two choices for the 16 bit timers: ck/1 or ck/64
+    ocr = F_CPU / frequency / 2 - 1;
+
+    prescalarbits = 0b001;    // CLKio/1
+    if (ocr > 0xffff) {
+        ocr = F_CPU / frequency / 2 / 64 - 1;
+        prescalarbits = 0b011;  // CLKio/64
+    }
+    TCCR1B = (TCCR1B & 0b11111000) | prescalarbits;
+
+    // Calculate the toggle count
+    if (duration > 0) {
+        toggle_count = 2 * frequency * duration / 1000;
+    } else {
+        toggle_count = -1;
+    }
+
+    uint8_t sreg = SREG;
+    cli();
+    OCR1AH = (ocr >> 8) & 0xff;
+    OCR1AL = ocr & 0xff;
+    SREG = sreg;
+
+    // enable interrupt
+    TIMSK1 |= (1<<OCIE1A);
+}
+
+// XXX: this function only works properly for timer 2 (the only one we use
+// currently).  for the others, it should end the tone, but won't restore
+// proper PWM functionality for the timer.
+void disableTimer(void)
+{
+    // disable interrupt
+    TIMSK1 &= ~(1<<OCIE1A);
+
+    TCCR1A = 0;
+    TCCR1B = 0;
+
+    uint8_t sreg = SREG;
+    cli();
+    OCR1AH = 0;
+    OCR1AL = 0;
+    SREG = sreg;
+}
+
+void noTone(void)
+{
+    disableTimer();
+    BZ_PIN_PORT &= ~(BZ_PIN_MASK);
+}
+
+ISR(TIMER1_COMPA_vect)
+{
+    if (toggle_count != 0) {
+        // toggle the pin
+        BZ_PIN_PORT ^= BZ_PIN_MASK;
+
+        if (toggle_count > 0)
+            toggle_count--;
+    } else {
+        disableTimer();
+        BZ_PIN_PORT &= ~(BZ_PIN_MASK);
+    }
+}
+