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

2022-09-20 01:08:01 -04:00
parent d0cbc0000e
commit 361a828c46
295 changed files with 68746 additions and 0 deletions
--- a/Examples/Chapter09_Introduction-to-Timer-Counter-Hardware/reactionTimer/reactionTimer.c
+++ b/Examples/Chapter09_Introduction-to-Timer-Counter-Hardware/reactionTimer/reactionTimer.c
@@ -0,0 +1,68 @@
+/*
+   Press the button as quickly as you can after the LEDs light up.
+   Your time is printed out over the serial port.
+*/
+
+// ------- Preamble -------- //
+#include <avr/io.h>
+#include <util/delay.h>
+#include <avr/interrupt.h>
+#include "pinDefines.h"
+#include "USART.h"
+
+#include "support.h"
+
+static inline void initTimer1(void) {
+                               /* Normal mode (default), just counting */
+  TCCR1B |= (1 << CS11) | (1 << CS10);
+  /* Clock speed: 1 MHz / 64,
+     each tick is 64 microseconds ~= 15.6 per ms  */
+                                            /* No special output modes */
+}
+
+int main(void) {
+  uint16_t timerValue;
+
+  // -------- Inits --------- //
+
+  initUSART();
+  initTimer1();
+  LED_DDR = 0xff;                               /* all LEDs for output */
+  BUTTON_PORT |= (1 << BUTTON);             /* enable internal pull-up */
+
+  printString("\r\nReaction Timer:\r\n");
+  printString("---------------\r\n");
+  printString("Press any key to start.\r\n");
+
+  // ------ Event loop ------ //
+  while (1) {
+
+    receiveByte();                                    /* press any key */
+    printString("\r\nGet ready...");
+    randomDelay();
+
+    printString("\r\nGo!\r\n");
+    LED_PORT = 0xff;                                     /* light LEDs */
+    TCNT1 = 0;                                        /* reset counter */
+
+    if (bit_is_clear(BUTTON_PIN, BUTTON)) {
+            /* Button pressed _exactly_ as LEDs light up.  Suspicious. */
+      printString("You're only cheating yourself.\r\n");
+    }
+    else {
+      // Wait until button pressed, save timer value.
+      loop_until_bit_is_clear(BUTTON_PIN, BUTTON);
+      timerValue = TCNT1 >> 4;
+      /* each tick is approx 1/16 milliseconds, so we bit-shift divide */
+
+      printMilliseconds(timerValue);
+      printComments(timerValue);
+    }
+
+    // Clear LEDs and start again.
+    LED_PORT = 0x00;
+    printString("Press any key to try again.\r\n");
+
+  }                                                  /* End event loop */
+  return 0;                            /* This line is never reached */
+}