Started following some tutorial on att85 usi. Downloaded example code from make avr book.

Make AVR Examples/Chapter10_Pulse-Width-Modulation/pwm/pwm.c

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+                                           /* Quick and dirty PWM Demo */
+
+// ------- Preamble -------- //
+#include <avr/io.h>                        /* Defines pins, ports, etc */
+#include <util/delay.h>                     /* Functions to waste time */
+#include "pinDefines.h"
+
+#define LED_DELAY  20                                  /* microseconds */
+
+void pwmAllPins(uint8_t brightness) {
+  uint8_t i;
+  LED_PORT = 0xff;                                          /* turn on */
+  for (i = 0; i < 255; i++) {
+    if (i >= brightness) {            /* once it's been on long enough */
+      LED_PORT = 0;                                        /* turn off */
+    }
+    _delay_us(LED_DELAY);
+  }
+}
+
+int main(void) {
+
+  uint8_t brightness = 0;
+  int8_t direction = 1;
+
+  // -------- Inits --------- //
+
+  // Init all LEDs
+  LED_DDR = 0xff;
+  // ------ Event loop ------ //
+  while (1) {
+    // Brighten and dim
+    if (brightness == 0) {
+      direction = 1;
+    }
+    if (brightness == 255) {
+      direction = -1;
+    }
+    brightness += direction;
+    pwmAllPins(brightness);
+
+
+  }                                                  /* End event loop */
+  return 0;                            /* This line is never reached */
+}