writing speed is detected, and the model mayhem sets backlight according to

speed

firmware/main.c

@@ -523,6 +523,49 @@ void sendString(char* string) {
     }
 }
 
+/**
+ * Calculate an average value for the speed the keys are pressed in. The speed
+ * value is sent to the keyboard interface, the keyboard decides what to do
+ * with it.
+ * \param updates number of updates since the last call (should be in the range
+ * 0-1)
+ */
+void calculateSpeed(uint8_t updates) {
+    static uint8_t callcounter = 0;
+    static uint8_t speed = 0;
+    callcounter++;
+    if (updates > 0) {
+        // a key has been pressed
+        if (speed < 251) {
+            // it can get hotter...
+            if (callcounter < 8) {
+                speed += 4;
+            } else if (callcounter < 16) {
+                speed += 3;
+            } else if (callcounter < 24) {
+                speed += 2;
+            } else {
+                speed += 1;
+            }
+            setSpeed(speed);
+        }
+        callcounter = 0;
+    } else {
+        // no key pressed...
+        if (callcounter == 16) {
+            // ... for a long time, decrease speed value
+            if (speed > 10) {
+                speed -= 10;
+                setSpeed(speed);
+            } else if (speed > 0) {
+                speed = 0;
+                setSpeed(speed);
+            }
+            callcounter = 0;
+        }
+    }
+}
+
 /**
  * Main function, containing the main loop that manages timer- and
  * USB-functionality.
@@ -531,6 +574,7 @@ void sendString(char* string) {
 int main(void) {
     uint8_t updateNeeded = 0;
     uint8_t idleCounter = 0;
+    uint8_t updates = 0;
     wdt_enable(WDTO_2S);
     hardwareInit();
     usbInit();
@@ -545,10 +589,15 @@ int main(void) {
         usbPoll();
 
         updateNeeded = scankeys(reportBuffer, oldReportBuffer, sizeof(reportBuffer)); // changes?
+        if (updateNeeded) {
+            updates++;
+        }
 
         // check timer if we need periodic reports
         if (TIFR & (1 << TOV0)) {
             TIFR = (1 << TOV0); // reset flag
+            calculateSpeed(updates);
+            updates = 0;
             if (idleRate != 0) { // do we need periodic reports?
                 if(idleCounter > 4){ // yes, but not yet
                     idleCounter -= 5; // 22ms in units of 4ms

firmware/modelibmmodelm.c

@@ -106,6 +106,10 @@ void printMatrix(void) {
     sendString("---");
 }
 
+void setSpeed(uint8_t speed) {
+    // not used in this model/version
+}
+
 void setLeds(uint8_t LEDstate) {
     if (LEDstate & LED_NUM) { // light up num lock
         PORTLEDS &= ~(1 << LEDNUM);

firmware/modelinterface.h

@@ -21,6 +21,13 @@ void hardwareInit(void);
  */
 void printMatrix(void);
 
+/**
+ * This tells the current writing speed to the keyboard, for whatever it will
+ * do with the value.
+ * \param speed speed value between 0 and 255
+ */
+void setSpeed(uint8_t speed);
+
 /**
  * This function sets the LEDs according to the given data.
  * \param LEDstate bitfield with LED info

firmware/modelmayhem.c

@@ -70,6 +70,21 @@ void hardwareInit(void) {
     PORTLEDS &= ~((1 << LEDNUM) | (1 << LEDCAPS) | (1 << LEDSCROLL) | (1 << LEDCOMP));
     _delay_ms(50);
     PORTLEDS |= ((1 << LEDNUM) | (1 << LEDCAPS) | (1 << LEDSCROLL) | (1 << LEDCOMP));
+
+    // initialize timer for pulse width modulation on backlight LED ports
+    // WGM13=1, WGM12=1, WGM11=1, WGM10=0 -> PWM mode 14
+    // COM1A1=1, COM1B1=1 -> OC1A and OC1B are set at the bottom and cleared on
+    //                       when the counter matches OCR1A or OCR1B
+    // CS10=1 -> prescaler 1
+    TCCR1A = (1 << COM1A1) | (1 << COM1B1) | (1 << WGM11);
+    TCCR1B = (1 << WGM13) | (1 << WGM12) | (1 << CS10);
+
+    // the pwm counter counts from 0 to this value
+    ICR1 = 0xffff;
+
+    // both LEDs are switched off on startup
+    OCR1A = 0xffff; // red
+    OCR1B = 0xffff; // green
 }
 
 /**
@@ -101,6 +116,11 @@ void printMatrix(void) {
     sendString("---");
 }
 
+void setSpeed(uint8_t speed) {
+    OCR1A = 0xffff - (speed * speed);
+    OCR1B = (speed * speed);
+}
+
 void setLeds(uint8_t LEDstate) {
     if (LEDstate & LED_NUM) { // light up num lock
         PORTLEDS &= ~(1 << LEDNUM);

firmware/modelsuntype5.c

@@ -93,6 +93,10 @@ void printMatrix(void) {
     sendString("\n");
 }
 
+void setSpeed(uint8_t speed) {
+    // not used in this model/version
+}
+
 void setLeds(uint8_t LEDstate) {
     if (LEDstate & LED_NUM) { // light up num lock
         PORTLEDS &= ~(1 << LEDNUM);