From 2442e4332259e6a774d5873681a3d1d1f3177917 Mon Sep 17 00:00:00 2001
From: "Michael D. M. Dryden" <mdryden@chem.utoronto.ca>
Date: Thu, 13 Aug 2015 19:12:49 -0400
Subject: [PATCH] Added position tracking and homing code

---
 main.c | 52 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 43 insertions(+), 9 deletions(-)

diff --git a/main.c b/main.c
index 3c033d1..dcd1c44 100644
--- a/main.c
+++ b/main.c
@@ -12,12 +12,15 @@
 #include <avr/interrupt.h>
 
 //Internal global variables
-bool current_dir = 1;
-uint16_t step_counter = 0;
+volatile bool current_dir = 1;
+volatile uint16_t step_counter = 0;
+int32_t z_position = 0;
 
 //Internal function declarations
 void single_step(void);
-void multi_step(bool dir, uint16_t steps, uint16_t steps_per_s);
+uint16_t multi_step(bool dir, uint16_t steps, uint16_t steps_per_s);
+//uint16_t mm_step(double mm, double mm_per_s, bool dir);
+bool home(void);
 
 void single_step(void){
     static bool last_dir = 1;
@@ -28,6 +31,13 @@ void single_step(void){
         last_dir = current_dir;
     }
     
+    if (current_dir) {
+        ++z_position;
+    }
+    else {
+        --z_position;
+    }
+    
     ioport_set_pin_level(PIN_STEP, 1);
     delay_us(10);
     ioport_set_pin_level(PIN_STEP, 0);
@@ -36,7 +46,7 @@ void single_step(void){
     return;
 }
 
-void multi_step(bool dir, uint16_t steps, uint16_t us_per_step){
+uint16_t multi_step(bool dir, uint16_t steps, uint16_t us_per_step){
     current_dir = dir;
     step_counter = 0;
     
@@ -50,14 +60,38 @@ void multi_step(bool dir, uint16_t steps, uint16_t us_per_step){
     TCNT1 = 0;
     TCCR1B |= TC1_DIV; // Start Timer
     
-    while (step_counter < steps); // wait until all steps done
+    while (step_counter < steps){ // wait until all steps done
+        if (ioport_get_pin_level(PIN_ZMIN) == 0) {
+            TIMSK1 &= ~(1 << OCIE1A);
+            TCCR1B &= ~(0b00000111);
+            return step_counter;
+        }
+    }
+
     
     // stop timer
-    
     TIMSK1 &= ~(1 << OCIE1A);
     TCCR1B &= ~(0b00000111);
+    
+    return 0;
+}
+
+//uint16_t mm_step(double mm, double mm_per_s, bool dir){
+//    multi_step(dir, (uint16_t)mm, (uint16_t)mm_per_s); // mm/steps_per_mm, mm_per_s -> us_per_step
+//}
+//
+//void home(void){
+//    while (multi_step(0, 1000, )) {
+//        <#statements#>
+//    }
+//}
+bool home(void){
+    while (multi_step(0, 1600, 400) == 0);
+    z_position = 0;
+    return 1;
 }
 
+
 int main(void){
 	
 	board_init();
@@ -65,10 +99,10 @@ int main(void){
     cpu_irq_enable(); // enable interrupts
     
 	delay_ms(500);
-	
+    
     while (1) {
-        multi_step(1, 40, 2000);
-        multi_step(0, 40, 2000);
+        home();
+        delay_s(10);
     }
 }
 
-- 
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