Add breathing sleep LED during USB suspend

common.mk

@@ -47,5 +47,11 @@ ifdef $(or MOUSEKEY_ENABLE, PS2_MOUSE_ENABLE)
     OPT_DEFS += -DMOUSE_ENABLE
 endif
 
+ifdef SLEEP_LED_ENABLE
+    SRC += $(COMMON_DIR)/sleep_led.c
+    OPT_DEFS += -DSLEEP_LED_ENABLE
+endif
+
+
 # Search Path
 VPATH += $(TOP_DIR)/common

common/sleep_led.c

@@ -0,0 +1,84 @@
+#include <stdint.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/pgmspace.h>
+#include "led.h"
+#include "sleep_led.h"
+
+/* Software PWM
+ *  ______           ______           __
+ * |  ON  |___OFF___|  ON  |___OFF___|   ....
+ * |<-------------->|<-------------->|<- ....
+ *     PWM period       PWM period
+ *
+ * 256              interrupts/period[resolution]
+ * 64               periods/second[frequency]
+ * 256*64           interrupts/second
+ * F_CPU/(256*64)   clocks/interrupt
+ */
+#define SLEEP_LED_TIMER_TOP F_CPU/(256*64)
+
+void sleep_led_init(void)
+{
+    /* Timer1 setup */
+    /* CTC mode */
+    TCCR1B |= _BV(WGM12);
+    /* Clock selelct: clk/1 */
+    TCCR1B |= _BV(CS10);
+    /* Set TOP value */
+    uint8_t sreg = SREG;
+    cli();
+    OCR1AH = (SLEEP_LED_TIMER_TOP>>8)&0xff;
+    OCR1AL = SLEEP_LED_TIMER_TOP&0xff;
+    SREG = sreg;
+}
+
+void sleep_led_enable(void)
+{
+    /* Enable Compare Match Interrupt */
+    TIMSK1 |= _BV(OCIE1A);
+}
+
+void sleep_led_disable(void)
+{
+    /* Disable Compare Match Interrupt */
+    TIMSK1 &= ~_BV(OCIE1A);
+}
+
+
+/* Breathing Sleep LED brighness(PWM On period) table
+ * (32[steps] * 8[duration]) / 64[PWM periods/s] = 4 second breath cycle
+ */
+static const uint8_t breathing_table[32] PROGMEM = {
+    0, 0, 0, 2, 9, 21, 37, 56, 78, 127, 151, 175, 197, 216, 232, 244,
+    254, 244, 216, 197, 175, 151, 127, 78, 56, 37, 21, 9, 2, 0, 0, 0
+};
+
+ISR(TIMER1_COMPA_vect)
+{
+    /* Software PWM
+     * timer:1111 1111 1111 1111
+     *       \----/\-/ \-------/+---  count(0-255)
+     *         |    +---------------  duration of step(8)
+     *         +--------------------  index of step table(0-31)
+     */
+    static union {
+        uint16_t row;
+        struct {
+            uint8_t count:8;
+            uint8_t duration:3;
+            uint8_t index:5;
+        } pwm;
+    } timer = { .row = 0 };
+
+    timer.row++;
+    
+    // LED on
+    if (timer.pwm.count == 0) {
+        led_set(1<<USB_LED_CAPS_LOCK);
+    }
+    // LED off
+    if (timer.pwm.count == pgm_read_byte(&breathing_table[timer.pwm.index])) {
+        led_set(0);
+    }
+}

common/sleep_led.h

@@ -0,0 +1,10 @@
+#ifndef SLEEP_LED_H
+#define SLEEP_LED_H
+
+#define NO_SUSPEND_POWER_DOWN
+
+void sleep_led_init(void);
+void sleep_led_enable(void);
+void sleep_led_disable(void);
+
+#endif

protocol/lufa/lufa.c

@@ -36,12 +36,20 @@
   this software.
 */
 
+#include <avr/sleep.h>
+#include <avr/wdt.h>
 #include "report.h"
 #include "host.h"
 #include "host_driver.h"
 #include "keyboard.h"
+#include "action.h"
+#include "matrix.h"
+#include "led.h"
 #include "sendchar.h"
 #include "debug.h"
+#ifdef SLEEP_LED_ENABLE
+#include "sleep_led.h"
+#endif
 
 #include "descriptor.h"
 #include "lufa.h"
@@ -140,10 +148,9 @@ static void Console_Task(void)
  * 2) EVENT_USB_Device_Reset
  * 3) EVENT_USB_Device_Wake
 */
-#include "led.h"
-#include "matrix.h"
 void EVENT_USB_Device_Connect(void)
 {
+    led_set(0x1f);  // all on
 }
 
 void EVENT_USB_Device_Disconnect(void)
@@ -156,17 +163,21 @@ void EVENT_USB_Device_Reset(void)
 
 void EVENT_USB_Device_Suspend()
 {
+#ifdef SLEEP_LED_ENABLE
+    sleep_led_enable();
+#endif
 }
 
-#include "action.h"
 void EVENT_USB_Device_WakeUp()
 {
     // initialize
     matrix_init();
     clear_keyboard();
 
-    // turn off LED
-    led_set(0);
+#ifdef SLEEP_LED_ENABLE
+    sleep_led_disable();
+#endif
+    led_set(host_keyboard_leds());
 }
 
 void EVENT_USB_Device_StartOfFrame(void)
@@ -493,7 +504,6 @@ static void SetupHardware(void)
 }
 
 
-#include "matrix.h"
 static bool wakeup_condition(void)
 {
     matrix_scan();
@@ -503,8 +513,6 @@ static bool wakeup_condition(void)
     return false;
 }
 
-#include <avr/sleep.h>
-#include <avr/wdt.h>
 #define wdt_intr_enable(value)   \
 __asm__ __volatile__ (  \
     "in __tmp_reg__,__SREG__" "\n\t"    \
@@ -527,11 +535,15 @@ int main(void)
     SetupHardware();
     keyboard_init();
     host_set_driver(&lufa_driver);
+#ifdef SLEEP_LED_ENABLE
+    sleep_led_init();
+#endif
     sei();
 
     while (1) {
         // while suspend
         while (USB_DeviceState == DEVICE_STATE_Suspended) {
+#ifndef NO_SUSPEND_POWER_DOWN
             // Enable watchdog to wake from MCU sleep
             cli();
             wdt_reset();
@@ -558,6 +570,7 @@ int main(void)
 
             // Disable watchdog after sleep
             wdt_disable();
+#endif
 
             // Send request of USB Wakeup from Suspend to host
             if (USB_Device_RemoteWakeupEnabled) {
@@ -575,9 +588,12 @@ int main(void)
     }
 }
 
-/* watchdog timeout during sleep */
+#ifndef NO_SUSPEND_POWER_DOWN
+/* watchdog timeout */
 ISR(WDT_vect)
 {
+    /* wakeup from MCU sleep mode */
+/*
     // blink LED
     static uint8_t led_state = 0;
     static uint8_t led_count = 0;
@@ -585,4 +601,6 @@ ISR(WDT_vect)
     if ((led_count & 0x07) == 0) {
         led_set((led_state ^= (1<<USB_LED_CAPS_LOCK)));
     }
+*/
 }
+#endif