From 02939ab1d831ab7bb02edb28cb0b21fb61bced56 Mon Sep 17 00:00:00 2001
From: tmk <nobody@nowhere>
Date: Thu, 4 Sep 2014 05:30:00 +0900
Subject: Add battery management

---
 keyboard/hhkb_rn42/rn42/battery.c | 119 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 keyboard/hhkb_rn42/rn42/battery.c

(limited to 'keyboard/hhkb_rn42/rn42/battery.c')

diff --git a/keyboard/hhkb_rn42/rn42/battery.c b/keyboard/hhkb_rn42/rn42/battery.c
new file mode 100644
index 000000000..32de86448
--- /dev/null
+++ b/keyboard/hhkb_rn42/rn42/battery.c
@@ -0,0 +1,119 @@
+#include <avr/io.h>
+#include <util/delay.h>
+#include "battery.h"
+
+
+/*
+ * Battery
+ */
+void battery_init(void)
+{
+    // blink 
+    battery_led(LED_ON);  _delay_ms(500);
+    battery_led(LED_OFF); _delay_ms(500);
+    battery_led(LED_ON);  _delay_ms(500);
+    battery_led(LED_OFF); _delay_ms(500);
+    // LED indicates charger status
+    battery_led(LED_CHARGER);
+
+    // ADC setting for voltage monitor
+    // Ref:2.56V band-gap, Input:ADC0(PF0), Prescale:128(16MHz/128=125KHz)
+    ADMUX = (1<<REFS1) | (1<<REFS0);
+    ADCSRA = (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0);
+    ADCSRA |= (1<<ADEN);
+}
+
+// Indicator for battery
+void battery_led(battery_led_t val)
+{
+    if (val == LED_TOGGLE) {
+        // Toggle LED
+        DDRF  |=  (1<<5);
+        PINF  |=  (1<<5);
+    } else if (val == LED_ON) {
+        // On overriding charger status
+        DDRF  |=  (1<<5);
+        PORTF &= ~(1<<5);
+    } else if (val == LED_OFF) {
+        // Off overriding charger status
+        DDRF  |=  (1<<5);
+        PORTF |=  (1<<5);
+    } else {
+        // Display charger status
+        DDRF  &= ~(1<<5);
+        PORTF &= ~(1<<5);
+    }
+}
+
+bool battery_charging(void)
+{
+    if (!(USBSTA&(1<<VBUS))) return false;
+
+    // MCP73831:STAT
+    //   HiZ:    Shutdown/No Battery
+    //   Low:    Charging
+    //   Hi:     Charged
+
+    // preserve last register status
+    uint8_t ddrf_prev  = DDRF;
+    uint8_t portf_prev = PORTF;
+
+    // Input with pullup
+    DDRF  &= ~(1<<5);
+    PORTF |=  (1<<5);
+    _delay_ms(1);
+    bool charging = PINF&(1<<5) ? false : true;
+
+    // restore last register status
+    DDRF  = (DDRF&~(1<<5))  | (ddrf_prev&(1<<5));
+    PORTF = (PORTF&~(1<<5)) | (portf_prev&(1<<5));
+
+    return charging;
+}
+
+// Returns voltage in mV
+uint16_t battery_voltage(void)
+{
+    volatile uint16_t bat;
+    //ADCSRA |= (1<<ADEN);
+
+    // discard first result
+    ADCSRA |= (1<<ADSC);
+    while (ADCSRA & (1<<ADSC)) ;
+    bat = ADC;
+
+    // discard second result
+    ADCSRA |= (1<<ADSC);
+    while (ADCSRA & (1<<ADSC)) ;
+    bat = ADC;
+
+    ADCSRA |= (1<<ADSC);
+    while (ADCSRA & (1<<ADSC)) ;
+    bat = ADC;
+
+    //ADCSRA &= ~(1<<ADEN);
+
+    return (bat - BATTERY_ADC_OFFSET) * BATTERY_ADC_RESOLUTION;
+}
+
+static bool low_voltage(void) {
+    static bool low = false;
+    uint16_t v = battery_voltage();
+    if (v < BATTERY_VOLTAGE_LOW_LIMIT) {
+        low = true;
+    } else if (v > BATTERY_VOLTAGE_LOW_RECOVERY) {
+        low = false;
+    }
+    return low;
+}
+
+battery_status_t battery_status(void)
+{
+    if (USBSTA&(1<<VBUS)) {
+        /* powered */
+        return battery_charging() ? CHARGING : FULL_CHARGED;
+    } else {
+        /* not powered */
+        return low_voltage() ? LOW_VOLTAGE : DISCHARGING;
+    }
+}
-- 
cgit v1.2.3


From 3b81ffc16c8cdf260c25f0778d32c721af4f105c Mon Sep 17 00:00:00 2001
From: tmk <nobody@nowhere>
Date: Thu, 4 Sep 2014 17:08:23 +0900
Subject: Monitor battery and alert low voltage

---
 keyboard/hhkb_rn42/rn42/battery.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

(limited to 'keyboard/hhkb_rn42/rn42/battery.c')

diff --git a/keyboard/hhkb_rn42/rn42/battery.c b/keyboard/hhkb_rn42/rn42/battery.c
index 32de86448..c6988fe33 100644
--- a/keyboard/hhkb_rn42/rn42/battery.c
+++ b/keyboard/hhkb_rn42/rn42/battery.c
@@ -49,10 +49,11 @@ bool battery_charging(void)
 {
     if (!(USBSTA&(1<<VBUS))) return false;
 
-    // MCP73831:STAT
-    //   HiZ:    Shutdown/No Battery
-    //   Low:    Charging
-    //   Hi:     Charged
+    // Charger Status:
+    //   MCP73831   MCP73832   LTC4054  Status
+    //   Hi-Z       Hi-Z       Hi-Z     Shutdown/No Battery
+    //   Low        Low        Low      Charging
+    //   Hi         Hi-Z       Hi-Z     Charged
 
     // preserve last register status
     uint8_t ddrf_prev  = DDRF;
@@ -68,6 +69,10 @@ bool battery_charging(void)
     DDRF  = (DDRF&~(1<<5))  | (ddrf_prev&(1<<5));
     PORTF = (PORTF&~(1<<5)) | (portf_prev&(1<<5));
 
+    // TODO: With MCP73831 this can not get stable status when charging.
+    // LED is powered from PSEL line(USB or Lipo)
+    // due to weak low output of STAT pin?
+    // due to pull-up'd via resitor and LED?
     return charging;
 }
 
-- 
cgit v1.2.3


From 2015027da325e9f9b602af1f36ceeeebbcd6c78d Mon Sep 17 00:00:00 2001
From: tmk <nobody@nowhere>
Date: Sat, 20 Sep 2014 06:12:49 +0900
Subject: Add FET swtich for battery ADC

---
 keyboard/hhkb_rn42/rn42/battery.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'keyboard/hhkb_rn42/rn42/battery.c')

diff --git a/keyboard/hhkb_rn42/rn42/battery.c b/keyboard/hhkb_rn42/rn42/battery.c
index c6988fe33..0320e1baf 100644
--- a/keyboard/hhkb_rn42/rn42/battery.c
+++ b/keyboard/hhkb_rn42/rn42/battery.c
@@ -21,6 +21,10 @@ void battery_init(void)
     ADMUX = (1<<REFS1) | (1<<REFS0);
     ADCSRA = (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0);
     ADCSRA |= (1<<ADEN);
+
+    // ADC disable voltate divider(PF4)
+    DDRF  |=  (1<<4);
+    PORTF &= ~(1<<4);
 }
 
 // Indicator for battery
@@ -79,6 +83,10 @@ bool battery_charging(void)
 // Returns voltage in mV
 uint16_t battery_voltage(void)
 {
+    // ADC disable voltate divider(PF4)
+    DDRF  |=  (1<<4);
+    PORTF |=  (1<<4);
+
     volatile uint16_t bat;
     //ADCSRA |= (1<<ADEN);
 
@@ -98,6 +106,10 @@ uint16_t battery_voltage(void)
 
     //ADCSRA &= ~(1<<ADEN);
 
+    // ADC disable voltate divider(PF4)
+    DDRF  |=  (1<<4);
+    PORTF &= ~(1<<4);
+
     return (bat - BATTERY_ADC_OFFSET) * BATTERY_ADC_RESOLUTION;
 }
 
-- 
cgit v1.2.3