deepsleep.py, pycoproc.py: Improve calibration functions.

Author: Daniel Campora

deepsleep/deepsleep.py

@@ -29,7 +29,7 @@ class DeepSleep:
     EXP_RTC_PERIOD = const(7000)
 
     def __init__(self):
-        self.uart = UART(1, baudrate=10000, pins=(COMM_PIN, ), timeout_chars=3)
+        self.uart = UART(1, baudrate=10000, pins=(COMM_PIN, ), timeout_chars=5)
         self.clk_cal_factor = 1
         self.uart.read()
         # enable the weak pull-ups control
@@ -103,20 +103,20 @@ def calibrate(self):
 
         # setbits, but limit the number of received bytes to avoid confusion with pattern
         self._magic(CTRL_0_ADDR, 0xFF, 1 << 2, 0, 0)
-        self._pulses = pycom.pulses_get(COMM_PIN, 50)
-        self.uart.init(baudrate=10000, pins=(COMM_PIN, ), timeout_chars=3)
+        self.uart.deinit()
+        self._pulses = pycom.pulses_get(COMM_PIN, 150)
+        self.uart.init(baudrate=10000, pins=(COMM_PIN, ), timeout_chars=5)
+        idx = 0
+        for i in range(len(self._pulses)):
+            if self._pulses[i][1] > EXP_RTC_PERIOD:
+                idx = i
+                break
         try:
-            if len(self._pulses) > 6:
-                self.clk_cal_factor = (self._pulses[6][1] - self._pulses[4][1]) / EXP_RTC_PERIOD
-            else:
-                self.clk_cal_factor = (self._pulses[5][1] - self._pulses[3][1]) / EXP_RTC_PERIOD
+            self.clk_cal_factor = (self._pulses[idx][1] - self._pulses[(idx - 1)][1]) / EXP_RTC_PERIOD
         except:
-            pass
+            self.clk_cal_factor = 1
         if self.clk_cal_factor > 1.25 or self.clk_cal_factor < 0.75:
             self.clk_cal_factor = 1
-        # flush the buffer
-        self.uart.read()
-        self.get_wake_status()
 
     def enable_auto_poweroff(self):
         self.setbits(CTRL_0_ADDR, 1 << 1)

lib/pycoproc/pycoproc.py

@@ -232,15 +232,21 @@ def calibrate_rtc(self):
         self._write(bytes([CMD_CALIBRATE]), wait=False)
         self.i2c.deinit()
         Pin('P21', mode=Pin.IN)
-        pulses = pycom.pulses_get('P21', 20000)
+        pulses = pycom.pulses_get('P21', 100)
         self.i2c.init(mode=I2C.MASTER, pins=(self.sda, self.scl))
-        period = 0
+        idx = 0
+        for i in range(len(pulses)):
+            if pulses[i][1] > EXP_RTC_PERIOD:
+                idx = i
+                break
         try:
-            period = pulses[2][1] - pulses[0][1]
+            period = pulses[idx][1] - pulses[(idx - 1)][1]
         except:
-            pass
+            period = 0
         if period > 0:
-            self.clk_cal_factor = ((EXP_RTC_PERIOD * 1.0) / period) * (1000.0 / 1024.0)
+            self.clk_cal_factor = (EXP_RTC_PERIOD / period) * (1000 / 1024)
+        if self.clk_cal_factor > 1.25 or self.clk_cal_factor < 0.75:
+            self.clk_cal_factor = 1
 
     def button_pressed(self):
         button = self.peek_memory(PORTA_ADDR) & (1 << 3)