optimized the LED and buzzer wiring

* since we use timer 3 exclusively for the buzzer but trigger the pin
  using an IRQ handler, there is no longer any need to occupy a high-resolution
  pin for the buzzer.
* PD5 became a new high resolution LED
* PD0 became the new buzzer pin
* rearranged the pins used for the different LEDs so that the distribution
  of high-resolution LEDs is symmetric
* Timer 0 is no longer used/modified by setting LEDs.
  This avoids some workarounds as timer 0 is also used by tmk's timer module.
* The song routines could be slightly improved using the timer module.
* documented the LED and buzzer pinout in README

1 files changed, 9 insertions, 14 deletions

diff --git a/led.c b/led.c
index c7e5933..0d92563 100644
--- a/led.c
+++ b/led.c
@@ -40,33 +40,28 @@ void led_set(uint8_t usb_led)
     else
         PORTD |= (1 << PD3);
 
-    /*
-     * 1st LED on first row (G00).
-     *
-     * NOTE: This will automatically disable PWM mode, so it will not
-     * interfere with timer 0 and tmk's timer module.
-     */
-    pwm_pd0_set_led(usb_led & (1 << USB_LED_NUM_LOCK) ? 255 : 0);
+    /* 1st LED on first row (G00). */
+    pwm_pb5_set_led(usb_led & (1 << USB_LED_NUM_LOCK) ? 255 : 0);
 
     /* 2nd LED on first row (G01): Highlight keyclick mode. */
-    pwm_pb7_set_led(keyclick_mode*255/(KEYCLICK_MAX-1));
+    pwm_pd1_set_led(keyclick_mode*255/(KEYCLICK_MAX-1));
 
     /* 3rd LED on the first row (G02) */
-    pwm_pd1_set_led(usb_led & (1 << USB_LED_COMPOSE) ? 255 : 0);
+    pwm_pb7_set_led(usb_led & (1 << USB_LED_COMPOSE) ? 255 : 0);
 
     /*
      * 4th LED (G03) are currently not triggerable via USB.
      * Could be triggered as the "backlight".
      */
-    pwm_pb6_set_led(0);
+    pwm_pb4_set_led(0);
 
     /* 5th LED on the first row (G04) */
-    pwm_pb4_set_led(usb_led & (1 << USB_LED_SCROLL_LOCK) ? 255 : 0);
+    pwm_pb6_set_led(usb_led & (1 << USB_LED_SCROLL_LOCK) ? 255 : 0);
 
     /*
      * 6th LED on the first row (G53).
      *
-     * Triggering this LED (PD2) will also enable the buzzer (PB5),
+     * Triggering this LED (PD2) will also enable the buzzer (PD0),
      * so we have got a way to beep from userspace (see ./k7637-beep.sh).
      *
      * The original firmware also had the error display on G53
@@ -74,9 +69,9 @@ void led_set(uint8_t usb_led)
      */
     if (usb_led & (1 << USB_LED_KANA)) {
         PORTD &= ~(1 << PD2);
-        pwm_pb5_set_tone(2200);
+        pwm_pd0_set_tone(2200);
     } else {
         PORTD |= (1 << PD2);
-        pwm_pb5_set_tone(0);
+        pwm_pd0_set_tone(0);
     }
 }