Ok so I have the code below for real-time graphing some data from an embedded device received over serial. It's not meant to be a production tool but rather an internal eng tool, hence it's not terribly user-friendly. The problem is that no matter what I do, I can't get minor grid lines to appear, even though here they are set to True, which=both. I can do anything I want to the major grid lines but the minors won't appear. Any ideas? Here is the code:
import numpy as np from matplotlib import pyplot as plt from matplotlib import animation import serial SERIAL_PORT_NUM=9 ...a bunch of constants... #windows starts serial port numbers at 1, python starts at 0 SERIAL_PORT_NUM = SERIAL_PORT_NUM - 1 """ Open the serial port """ ser =serial.Serial(port=SERIAL_PORT_NUM,baudrate=115200,bytesize=8,parity='N',stopbits=1,timeout=None,xonxoff=0,rtscts=0) # First set up the figure, the axis, and the plot element we want to animate raw_adc_fig = plt.figure() raw_adc_ax = plt.axes(xlim=(0, 200), ylim=(0, 2047)) raw_adc_ax.grid(True, which='both') raw_adc_fig.suptitle("Raw ADC data") plt.ylabel("ADC values (hex)") plt.xlabel("time (sec)") raw_adc_line, = raw_adc_ax.plot([], [], lw=2) def read_serial(serial_port): tmp = '' same_line = True while same_line: tmp += serial_port.read(1) if tmp != '': if tmp[-1] == '*': same_line = False tmp = tmp.rstrip() tmp = tmp.lstrip() return tmp def process_serial(input_data): output_data = 0 intermediate_data = input_data[A_TYPE_START_POS:A_TYPE_STOP_POS + 1] if( intermediate_data != ''): output_data = int(intermediate_data , 16 ) else: print "bad data" output_data = -100 return output_data def get_sound_value(serial_port): cur_line = '' get_next_line = True # read in the next line until a sound packet of type A is found while( get_next_line ): cur_line = read_serial(serial_port) if( (cur_line != '') and (cur_line[0:3] == ROUTER_SOUND_DATA) and (len(cur_line) == D_TYPE_STOP_POS + 2) ): get_next_line = False sound_value = process_serial(cur_line) return sound_value # initialization function: plot the background of each frame def raw_adc_init(): raw_adc_line.set_data([], []) return raw_adc_line, # animation function. This is called sequentially def raw_adc_animate(i): sound_data_list.append( get_sound_value(ser) ) y = sound_data_list if( len(y) == 190 ): del y[0] x = np.linspace(0, len(y), len(y)) raw_adc_line.set_data(x, y) return raw_adc_line, # call the animator. blit=True means only re-draw the parts that have changed. raw_adc_anim = animation.FuncAnimation(raw_adc_fig, raw_adc_animate, init_func=raw_adc_init, frames=200, interval=1000, blit=True) Edit: fixed a bug in opening the serial port. Changed timeout=0 to timeout=None.
