start penna zip

serial_dexp.py

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+# contact ST32 microcontroller via serial,
+# gather the single bytes we recieve and put them together (two by two),
+# plot the 16bits numbers.
+
+import serial
+import sys
+from matplotlib import pyplot as plt
+import numpy as np
+
+SERIAL_PORT = '/dev/ttyACM0'
+BAUDRATE = 115200
+TIMEOUT = 1
+
+CONTROL_CHAR = 'h'  # trigger char for sending data configured on the board
+
+# define the expected resulting function and plot it
+AMP = 40000
+TAU1 = 25
+TAU2 = 8
+def dexp(x):
+    exp1 = AMP * np.exp(-x/TAU1)
+    exp2 = AMP * np.exp(-x/TAU2)
+    return exp1-exp2
+x_coord = np.linspace(0,100,1000)
+plt.plot(x_coord, dexp(x_coord), linestyle='dashed', linewidth='0.7', color='blue', label='expected')
+
+# init serial port
+try:
+    ser = serial.Serial(SERIAL_PORT, BAUDRATE, timeout=TIMEOUT)
+except serial.SerialException as e:
+    print(f"Serial port init error: {e}")
+    sys.exit(1)
+
+# send the control char in ascii encoding (single byte)
+ser.write(CONTROL_CHAR.encode('ascii'))
+# read the full content being sent
+recieved = bytearray(ser.readall())
+# join the bytes two by two to get numbers back
+# (note: they were stored with little endianess i think, so set appropriate 'byteorder' value)
+numbers = [int.from_bytes(recieved[i:i+2], byteorder='little', signed=False) for i in range(0,len(recieved),2)]
+
+# plot the result (both the single points and the curve connecting them)
+plt.plot(range(0,100), numbers, linewidth='0.8', color='orange', label='result')
+plt.scatter(range(0,100), numbers, marker='+', color='orange')
+
+plt.legend()
+plt.grid(True)
+plt.show()
+
+ser.close()