adding servo code

README.md

@@ -31,8 +31,17 @@ cu is a "Call-Up" device meant for calling other devices (e.g. modems). Since we
 the dev board we will be using the `/dev/cu.SLAB_USBtoUART` character file for connecting to the board.
 
 ### Flashing your board
+ESP32
 
+```
+esptool.py --chip esp32 -p /dev/cu.SLAB_USBtoUART erase_flash
+```
+
+```
+esptool.py --chip esp32 --port /dev/cu.SLAB_USBtoUART --baud 115200 write_flash -z 0x1000 esp32spiram-idf3-20200902-v1.13.bin
+```
 
+ESP8266
 ```
 esptool.py -p /dev/cu.SLAB_USBtoUART erase_flash
 ```

basics/README.md

@@ -79,4 +79,15 @@ def free(full=False):
     else : return ('Total:{0} Free:{1} ({2})'.format(T,F,P))
 ```
 
-esptool.py --chip esp32 --port /dev/cu.SLAB_USBtoUART --baud 460800 write_flash -z 0x1000 ~/Desktop/esp32spiram-idf3-20200902-v1.13.bin
+# installing micropython on esp32
+
+1. Delete flash
+
+```
+esptool.py --port /dev/cu.SLAB_USBtoUART erase_flash
+```
+
+2. If you have external spi ram (4MB) you want to use the spiram bin.
+```
+esptool.py --chip esp32 --port /dev/cu.SLAB_USBtoUART --baud 460800 write_flash -z 0x1000 ./binaries/esp32-idf4-20210202-v1.14.bin
+```

motors/pwm/servo.py

@@ -0,0 +1,76 @@
+"""Default values provided are from the DS3218MG.
+
+Pins GPIOs 34 to 39 can’t generate PWM on the ESP32.
+
+Description:
+    High-precision metal gears with hard anodizing
+    CNC aluminum middle Shell
+    water proof rubber seals screws
+Specification:
+    Stall Torque (5V): 19 kg/cm (263.8oz/in)
+    Stall Torque (6.8V): 21.5 kg/cm (298.5 oz/in)
+    Dead band: 3μs
+    Speed : 0.16 sec/60°(5V) / 0.14 sec/60°(6.8V)
+    Operating Voltage: 4.8 ~ 6.8 DC Volts
+    Weight: 60 g (2.12 oz)
+    Motor Type: DC Motor
+    Gear Type: Copper & Aluminum
+    Working frequence: 1520μs / 333hz
+    CE Certification: Yes
+    Size: 40 x 20 x 40.5 mm ( 1.58 x 0.79 x 1.60 in)
+    Package Includes:
+    4 X DS3218 Digital Servo 20KG
+    4 X 25T Servo Arm
+
+micro-seconds on 10**-6 seconds.
+
+
+"""
+from machine import Pin, PWM
+import math
+
+
+class Servo:
+
+    def __init__(self, pin, freq=40, min_us=500, max_us=2500,
+                 degrees=270):
+        """
+        :param pin: machine.Pin
+            A PWM enabled Pin
+        :param freq: int
+            The frequency in Hz. Typical values for servos are 40 or 50.
+        :param min_us: int
+            The minimum number of microseconds
+        :param max_us:
+            The maximum number of microseconds
+        :param degrees: int
+            The range in degrees of the motor
+        """
+        self.period = 1000000 / freq
+        self.min_duty = self._us2duty(min_us)
+        self.max_duty = self._us2duty(max_us)
+        self.degrees = degrees
+        self.freq = freq
+        self.pin = PWM(pin, freq=freq)
+
+    def _us2duty(self, value):
+        """Converts a microsecond value to a duty cycle value."""
+        return int(1024 * value / self.period)
+
+    def position(self, degrees=None, radians=None, us=None, duty=None):
+        span = self.max_duty - self.min_duty  # 409.6
+        if degrees is not None:
+            duty = self.min_duty + span * degrees / self.degrees
+        elif radians is not None:
+            duty = self.min_duty + span * radians / math.radians(self.degrees)
+        elif us is not None:
+            duty = self._us2duty(us)
+        elif duty is not None:
+            pass
+        else:
+            return self.pin.duty()
+        duty = min(self.max_duty, max(self.min_duty, int(duty)))
+        self.pin.duty(duty)
+
+    def release(self):
+        self.pin.duty(0)

motors/pwm/servo_main.py

@@ -0,0 +1,25 @@
+from machine import Pin
+from servo import Servo
+from time import sleep
+
+p21 = Pin(21)
+
+s21 = Servo(p21, freq=50, min_us=500, max_us=2500,
+                 degrees=270)
+
+while True:
+    print("Position: 0")
+    s21.position(degrees=0)
+    sleep(2)
+    print("Position: 30")
+    s21.position(degrees=30)
+    sleep(2)
+    print("Position: 60")
+    s21.position(degrees=60)
+    sleep(2)
+    print("Position: 90")
+    s21.position(degrees=90)
+    sleep(2)
+    print("Position: 120")
+    s21.position(degrees=120)
+    sleep(2)