From 46b3520d9c20d0f7f56a9d83641a0a28b1354cf6 Mon Sep 17 00:00:00 2001
From: Dat Nguyen <nguy2854@umn.edu>
Date: Wed, 2 Oct 2019 10:36:22 -0500
Subject: Encoder class

---
 System_Python/encoder.py      | 74 +++++++++++++++++++++++++++++++++++++++++++
 System_Python/test_Encoder.py | 64 ++++++-------------------------------
 2 files changed, 84 insertions(+), 54 deletions(-)
 create mode 100644 System_Python/encoder.py

(limited to 'System_Python')

diff --git a/System_Python/encoder.py b/System_Python/encoder.py
new file mode 100644
index 0000000..b70fac6
--- /dev/null
+++ b/System_Python/encoder.py
@@ -0,0 +1,74 @@
+# Import required modules
+import RPi.GPIO as GPIO
+import time
+import math
+
+# Constants: parameters that the caller cannot modify
+# Delay: Minimum delay necessary after pull pin low to read input
+delay = 0.0000005
+
+# Encoder Class
+# This controls the motor at the given IO
+class Encoder:
+    def __init__(self, clk_pin, cs_pin, data_pin):
+        # Set the board IO (just in case it hasn't been done yet)
+        GPIO.setmode(GPIO.BCM)
+        # Setup class varaiable
+        self.offset=0
+        self.clk_pin = clk_pin
+        self.cs_pin = cs_pin
+        self.data_pin = data_pin
+        # Setup the IO
+        try:
+            GPIO.setup(self.clk_pin,GPIO.OUT)
+            GPIO.setup(self.cs_pin,GPIO.OUT)
+            GPIO.setup(self.data_pin,GPIO.IN)
+            # Setup the CS and CLK to be high
+            GPIO.output(PIN_CLK,1)
+            GPIO.output(PIN_CS,1)
+        except:
+            print("ERROR. Unable to setup the configuration required")
+        # Wait some time to before reading
+        time.sleep(0.5)
+    def setZero(self):
+        # Take current position as zero
+        self.offset=self.readPosition('Raw')
+    def clockup(self):
+        GPIO.output(self.clk_pin,1)
+    def clockdown(self):
+        GPIO.output(self.clk_pin,0)
+    def readPosition(self, format):
+        # Most of this is based of timing diagram of encoder
+        # Pull CS low to start reading
+        GPIO.output(self.cs_pin,0) 
+        # Delay necessary before reading is ready
+        time.sleep(delay*2)
+        data = 0
+        # Clockdown necessary before reading 
+        self.clockdown()
+        # Go through 10 bits needed to read
+        for i in range(0,10): 
+            # Clock up to start reading one bit
+            self.clockup()
+            # Shift data left and insert input 
+            data<<=1  
+            data|=GPIO.input(self.data_pin)
+            # Clock down after finish reading
+            self.clockdown()
+        # Pull CS high after finish reading
+        GPIO.output(self.cs_pin,1)
+        # Format with offset, Max is 1024
+        data=(data+offset)%1024
+        # Data is linearly mapped
+        if format=="Raw":
+            return data
+        elif format=="Degrees":
+            degrees=data/(1024/360)
+            return degrees
+        elif format=="Radian":
+            radians=data/(1024/(2*math.pi))
+            return radians
+        else:
+            print("ERROR. Invalid format (Raw, Degrees, Radians)")
+            return None
+    
diff --git a/System_Python/test_Encoder.py b/System_Python/test_Encoder.py
index ab74c6e..08804fa 100644
--- a/System_Python/test_Encoder.py
+++ b/System_Python/test_Encoder.py
@@ -1,58 +1,14 @@
+from encoder import Encoder
 import time
-import RPi.GPIO as GPIO
 
-GPIO.setmode(GPIO.BCM)
+# Decide which pins to hook up to on the Pi before running
+clk_pin = 2
+cs_pin  = 4
+data_pin = 3
 
-PIN_CLK = 2
-PIN_DATA = 3
-PIN_CS  = 4
-delay = 0.0000005
+e = Encoder(clk_pin, cs_pin, data_pin)
+e.setZero()
 
-# pin setup done here
-try:
-    GPIO.setup(PIN_CLK,GPIO.OUT)
-    GPIO.setup(PIN_DATA,GPIO.IN)
-    GPIO.setup(PIN_CS,GPIO.OUT)                                                                                                    
-    GPIO.output(PIN_CS,1)
-    GPIO.output(PIN_CLK,1)
-except:
-    print("ERROR. Unable to setup the configuration requested")                                    
-
-#wait some time to start
-time.sleep(0.5)
-
-print("GPIO configuration enabled")
-
-def clockup():
-    GPIO.output(PIN_CLK,1)
-def clockdown():
-    GPIO.output(PIN_CLK,0)
-
-def readpos():
-    GPIO.output(PIN_CS,0) #pulls low to start
-
-    time.sleep(delay*2)
-    data = 0
-    clockdown()
-    
-    time1=time.clock()
-    for i in range(0,10): #bitcount):
-        clockup() #375 ns between each
-        data<<=1  
-        data|=GPIO.input(PIN_DATA)
-        #while(time.clock()-time1<minReadValue);
-        clockdown()
-    print(time.clock()-time1)
-    GPIO.output(PIN_CS,1) #pull high after finish
-    
-    return data
-
-try:
-    while(1):
-        print(readpos())
-        time.sleep(0.001)
-        #break
-        
-finally:
-    print("cleaning up GPIO")
-    GPIO.cleanup()
\ No newline at end of file
+while(1):
+    print(e.readPosition('Degrees'))
+    time.sleep(0.001)
\ No newline at end of file
-- 
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