Add gain example

examples/ads1x15_gain_example.py

@@ -0,0 +1,40 @@
+import time
+import board
+import busio
+#import adafruit_ads1x15.ads1015 as ADS
+import adafruit_ads1x15.ads1115 as ADS
+from adafruit_ads1x15.analog_in import AnalogIn
+
+# Create the I2C bus
+i2c = busio.I2C(board.SCL, board.SDA)
+
+# Create the ADS object
+#ads = ADS.ADS1015(i2c)
+ads = ADS.ADS1115(i2c)
+
+# Create a sinlge ended channel on Pin 0
+#   Max counts for ADS1015 = 2047
+#                  ADS1115 = 32767
+chan = AnalogIn(ads, ADS.P0)
+
+# The ADS1015 and ADS1115 both have the same gain options.
+#
+#       GAIN    RANGE (V)
+#       ----    ---------
+#        2/3    +/- 6.144
+#          1    +/- 4.096
+#          2    +/- 2.048
+#          4    +/- 1.024
+#          8    +/- 0.512
+#         16    +/- 0.256
+#
+gains = (2/3, 1, 2, 4, 8, 16)
+
+while True:
+    ads.gain = gains[0]
+    print('{:5} {:5.3f}'.format(chan.value, chan.voltage), end='')
+    for gain in gains[1:]:
+        ads.gain = gain
+        print(' | {:5} {:5.3f}'.format(chan.value, chan.voltage), end='')
+    print()
+    time.sleep(0.5)