added recent code

frontend.py

@@ -17,7 +17,7 @@ WREG = 0x40
 
 class Reading:
     def __init__(self, values: [int]):
-        print(values)
+#         print(values)
         assert values[0] & 0xF0 == 0xC0, "Invalid readback"
         self.loff_statp = (values[0] & 0x0F) << 4 | (values[1] & 0xF0) >> 4
         self.loff_statn = (values[1] & 0x0F) << 4 | (values[2] & 0xF0) >> 4
@@ -28,7 +28,7 @@ class Reading:
             for i in range(8)
         ]
 
-        print(self.loff_statp, self.loff_statn, self.gpios, self._channels)
+#         print(self.loff_statp, self.loff_statn, self.gpios, self._channels)
 
     def channels(self):
         return self._channels
@@ -49,13 +49,14 @@ class Frontend:
     def __init__(self):
         self.nrst = GPIO("/dev/gpiochip2", 9, "out")
         self.pwdn = GPIO("/dev/gpiochip2", 12, "out")
-        self.start = GPIO("/dev/gpiochip3", 29, "out")
+        self._start = GPIO("/dev/gpiochip3", 29, "out")
+        self.drdy = GPIO("/dev/gpiochip3", 28, "in")
         self.dev = SpiDev()
         self.dev.open(0, 0)
-        self.dev.max_speed_hz = 8000000
+        self.dev.max_speed_hz = 1000000
         self.dev.mode = 0b01
 
-        self.start.write(False)
+        self._start.write(False)
         self.powerup()
         self.reset()
         self.stop_continuous()
@@ -94,5 +95,16 @@ class Frontend:
         values = self.dev.xfer([0x00] * 27)
         return Reading(values)
 
+    def start(self):
+        self._start.write(True)
+        self.dev.xfer([START])
+
+    def stop(self):
+        self._start.write(False)
+        self.dev.xfer([STOP])
+
+    def is_ready(self):
+        return not self.drdy.read()
+
     def close(self):
         self.dev.close()

prog.py

@@ -1,34 +1,62 @@
 from time import sleep
 from playsound import playsound
 import numpy as np
-import matplotlib as plt
+import matplotlib.pyplot as plt
 import os
+from datetime import datetime, timedelta
 
 from frontend import Frontend
 from leds import LEDs, Color
 
+DEFAULT_FRONTEND_CONFIG = [
+    0x3E, # ID (RO)
+    0x96, # Datarate = 250 SPS
+    0xC0, # No tests
+    0x60, # Power-down reference buffer, no bias
+    0x00, # No lead-off
+    0x61, # Channel 1 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 2 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 3 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 4 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 5 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 6 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 7 active, 24 gain, no SRB2 & input shorted
+    0x61, # Channel 8 active, 24 gain, no SRB2 & input shorted
+    0x00, # No bias
+    0x00, # No bias
+    0x00, # No lead-off
+    0x00, # No lead-off
+    0x00, # No lead-off flip
+    0x00, # Lead-off positive status (RO)
+    0x00, # Laed-off negative status (RO)
+    0x0F, # All GPIOs as inputs
+    0x00, # Disable SRB1
+    0x00, # Unused
+    0x00, # Single-shot, lead-off comparator disabled
+]
+
 FRONTEND_CONFIG = [
-    0x3E, # Overwrite ID?
+    0x3E, # ID (RO)
     0x95, # Datarate = 500 SPS
     0xC0, # No tests
-    0xE1, # Power-down reference buffer, no bias
+    0xE0, # Power-down reference buffer, no bias
     0x00, # No lead-off
-    0x60, # Channel 1 active, 24 gain, no SRB2 & normal input
-    0x60, # Channel 2 active, 24 gain, no SRB2 & normal input
-    0x60, # Channel 3 active, 24 gain, no SRB2 & normal input
-    0x60, # Channel 4 active, 24 gain, no SRB2 & normal input
-    0x60, # Channel 5 active, 24 gain, no SRB2 & normal input
-    0x60, # Channel 6 active, 24 gain, no SRB2 & normal input
-    0x60, # Channel 7 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 1 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 2 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 3 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 4 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 5 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 6 active, 24 gain, no SRB2 & normal input
+    0x68, # Channel 7 active, 24 gain, no SRB2 & normal input
     0xE0, # Channel 8 disabled, 24 gain, no SRB2 & normal input
     0x00, # No bias
     0x00, # No bias
     0xFF, # Lead-off on all positive pins?
     0xFF, # Lead-off on all negative pins?
     0x00, # Normal lead-off
-    0x00, # Lead-off positive status (RO) ?
-    0x01, # Lead-off negative status (RO) ?
-    0x00, # All GPIOs as output ???
+    0x00, # Lead-off positive status (RO)
+    0x00, # Lead-off negative status (RO)
+    0x00, # All GPIOs as output ?
     0x20, # Disable SRB1
 ]
 
@@ -42,9 +70,21 @@ try:
     leds.led2(Color.BLUE)
 
     print("Configuring EEG Frontend")
-    data = frontend.write_regs(0x00, FRONTEND_CONFIG)
+    frontend.write_regs(0x00, FRONTEND_CONFIG)
+    #config = DEFAULT_FRONTEND_CONFIG[:]
+    #config[0x02] = 0xD0 # Activate test signals
+    #config[0x03] = 0xE0 # Power-up reference buffer
+    #for i in range(0x05, 0x0D):
+    #    config[i] = 0x05 # Channel active, 1 gain, no SRB2 & Test signal
+    #frontend.write_regs(0x00, config)
+    data = frontend.read_regs(0x00, len(FRONTEND_CONFIG))
+    assert data == FRONTEND_CONFIG, f"Wrong config: {data} vs {FRONTEND_CONFIG}"
+    frontend.start()
     print("EEG Frontend configured")
     leds.led2(Color.PURPLE)
+    while not frontend.is_ready():
+        pass
+    print("Ready for data")
 
     leds.aquisition(True)
     sleep(0.5)
@@ -53,10 +93,29 @@ try:
     leds.aquisition(True)
 
     points = []
-    for x in range(2000):
-        sleep(0.001)
+    START = datetime.now()
+    NUM_STEPS = 2000
+    #times = [timedelta(milliseconds=i) for i in range(NUM_STEPS)]
+    times = [i / 250 for i in range(NUM_STEPS)]
+    for x in range(NUM_STEPS):
+        while not frontend.is_ready():
+            pass
         values = frontend.read()
         print(values.channels())
+        points.append(values.channels())
+        while frontend.is_ready():
+            pass
+    leds.aquisition(False)
+
+    points = np.transpose(np.array(points))
+    fig, ax = plt.subplots()
+    for i in [0]:#range(8):
+        ax.plot(times, points[i] * 4.5 / 2**24, label='channel #' + str(i))
+    ax.set_xlabel('Time since start (s)')
+    ax.set_ylabel('Value')
+    ax.set_title('Test readings')
+    ax.legend()
+    plt.savefig('readings.png')
 
 finally:
     frontend.close()