1 files changed, 75 insertions, 0 deletions
diff --git a/tk-voltage.h b/tk-voltage.h
new file mode 100644
index 0000000..a335447
--- /dev/null
+++ b/tk-voltage.h
@@ -0,0 +1,75 @@
+#ifndef TK_VOLTAGE_H
+#define TK_VOLTAGE_H
+/*
+ * Voltage / battcheck functions.
+ *
+ * Copyright (C) 2015 Selene ToyKeeper
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "tk-attiny.h"
+#include "tk-calibration.h"
+
+#ifdef VOLTAGE_MON
+inline void ADC_on() {
+    // disable digital input on ADC pin to reduce power consumption
+    DIDR0 |= (1 << ADC_DIDR);
+    // 1.1v reference, left-adjust, ADC1/PB2
+    ADMUX  = (1 << V_REF) | (1 << ADLAR) | ADC_CHANNEL;
+    // enable, start, prescale
+    ADCSRA = (1 << ADEN ) | (1 << ADSC ) | ADC_PRSCL;
+}
+
+uint8_t get_voltage() {
+    // Start conversion
+    ADCSRA |= (1 << ADSC);
+    // Wait for completion
+    while (ADCSRA & (1 << ADSC));
+    // Send back the result
+    return ADCH;
+}
+#else
+inline void ADC_off() {
+    ADCSRA &= ~(1<<7); //ADC off
+}
+#endif
+
+#ifdef USE_BATTCHECK
+PROGMEM const uint8_t voltage_blinks[] = {
+              // 0 blinks for less than 1%
+    ADC_0,    // 1 blink  for 1%-25%
+    ADC_25,   // 2 blinks for 25%-50%
+    ADC_50,   // 3 blinks for 50%-75%
+    ADC_75,   // 4 blinks for 75%-100%
+    ADC_100,  // 5 blinks for >100%
+    255,      // Ceiling, don't remove  (6 blinks means "error")
+};
+
+inline uint8_t battcheck() {
+    // Return an int, number of "blinks", for approximate battery charge
+    // Uses the table above for return values
+    uint8_t i, voltage;
+    voltage = get_voltage();
+    // figure out how many times to blink
+    for (i=0;
+         voltage > pgm_read_byte(voltage_blinks + i);
+         i ++) {}
+    return i;
+}
+#endif
+
+
+#endif  // TK_VOLTAGE_H