Add temperature, fix brightness, change how pins are toggled

Author: mcauser

setup.py

@@ -7,7 +7,7 @@
 setup(
     name='micropython-tm1637',
     py_modules=['tm1637'],
-    version='1.1.0',
+    version='1.2.0',
     description='MicroPython library for TM1637 LED driver.',
     long_description='This library lets you operate quad 7-segment LED display modules based on the TM1637 LED driver.',
     keywords='tm1637 seven segment led micropython',

tm1637.py

@@ -1,18 +1,20 @@
 # MicroPython TM1637 quad 7-segment LED display driver
 
+from micropython import const
 from machine import Pin
 from time import sleep_us
 
-_CMD_SET1 = const(64)  # 0x40 data set
-_CMD_SET2 = const(192) # 0xC0 address command set
-_CMD_SET3 = const(128) # 0x80 data control command set
+TM1637_CMD1 = const(64)  # 0x40 data command
+TM1637_CMD2 = const(192) # 0xC0 address command
+TM1637_CMD3 = const(128) # 0x80 display control command
+TM1637_DSP_ON = const(8) # 0x08 display on
+TM1637_DELAY = const(10) # 10us delay between clk/dio pulses
 
 # 0-9, a-f, blank, dash
 _SEGMENTS = [63,6,91,79,102,109,125,7,127,111,119,124,57,94,121,113,0,64]
 
 class TM1637(object):
-    """Library for the quad 7-segment LED display modules based on the TM1637
-    LED driver."""
+    """Library for quad 7-segment LED modules based on the TM1637 LED driver."""
     def __init__(self, clk, dio, brightness=7):
         self.clk = clk
         self.dio = dio
@@ -21,75 +23,80 @@ def __init__(self, clk, dio, brightness=7):
             raise ValueError("Brightness out of range")
         self._brightness = brightness
 
-        self.clk.init(Pin.IN)
-        self.dio.init(Pin.IN)
-        self.clk(0)
-        self.dio(0)
+        self.clk.init(Pin.OUT, value=0)
+        self.dio.init(Pin.OUT, value=0)
+        sleep_us(TM1637_DELAY)
+
+        self._write_data_cmd()
+        self._write_dsp_ctrl()
 
     def _start(self):
-        self.dio.init(Pin.OUT)
-        sleep_us(50)
+        self.dio(0)
+        sleep_us(TM1637_DELAY)
+        self.clk(0)
+        sleep_us(TM1637_DELAY)
 
     def _stop(self):
-        self.dio.init(Pin.OUT)
-        sleep_us(50)
-        self.clk.init(Pin.IN)
-        sleep_us(50)
-        self.dio.init(Pin.IN)
-        sleep_us(50)
-
-    def _write_comm1(self):
+        self.dio(0)
+        sleep_us(TM1637_DELAY)
+        self.clk(1)
+        sleep_us(TM1637_DELAY)
+        self.dio(1)
+
+    def _write_data_cmd(self):
+        # automatic address increment, normal mode
         self._start()
-        self._write_byte(_CMD_SET1)
+        self._write_byte(TM1637_CMD1)
         self._stop()
 
-    def _write_comm3(self):
+    def _write_dsp_ctrl(self):
+        # display on, set brightness
         self._start()
-        self._write_byte(_CMD_SET3 + self._brightness + 7)
+        self._write_byte(TM1637_CMD3 | TM1637_DSP_ON | self._brightness)
         self._stop()
 
     def _write_byte(self, b):
-        # send each bit
         for i in range(8):
-            self.clk.init(Pin.OUT)
-            sleep_us(50)
-            self.dio.init(Pin.IN if b & 1 else Pin.OUT)
-            sleep_us(50)
-            self.clk.init(Pin.IN)
-            sleep_us(50)
-            b >>= 1
-        self.clk.init(Pin.OUT)
-        sleep_us(50)
-        self.clk.init(Pin.IN)
-        sleep_us(50)
-        self.clk.init(Pin.OUT)
-        sleep_us(50)
+            self.dio((b >> i) & 1)
+            sleep_us(TM1637_DELAY)
+            self.clk(1)
+            sleep_us(TM1637_DELAY)
+            self.clk(0)
+            sleep_us(TM1637_DELAY)
+        self.clk(0)
+        sleep_us(TM1637_DELAY)
+        self.clk(1)
+        sleep_us(TM1637_DELAY)
+        self.clk(0)
+        sleep_us(TM1637_DELAY)
 
     def brightness(self, val=None):
         """Set the display brightness 0-7."""
+        # brightness 0 = 1/16th pulse width
+        # brightness 7 = 14/16th pulse width
         if val is None:
             return self._brightness
         if not 0 <= val <= 7:
             raise ValueError("Brightness out of range")
+
         self._brightness = val
-        self._write_comm1()
-        self._write_comm3()
+        self._write_data_cmd()
+        self._write_dsp_ctrl()
 
     def write(self, segments, pos=0):
         """Display up to 4 segments moving right from a given position.
         The MSB in the 2nd segment controls the colon between the 2nd
         and 3rd segments."""
         if not 0 <= pos <= 3:
             raise ValueError("Position out of range")
-        self._write_comm1()
-
-        # write COMM2 + first digit address
+        self._write_data_cmd()
         self._start()
-        self._write_byte(_CMD_SET2 + pos)
+
+        self._write_byte(TM1637_CMD2 | pos)
         for seg in segments:
             self._write_byte(seg)
         self._stop()
-        self._write_comm3()
+        self._write_dsp_ctrl()
 
     def encode_digit(self, digit):
         """Convert a character 0-9, a-f to a segment."""
@@ -146,3 +153,13 @@ def numbers(self, num1, num2, colon=True):
         if colon:
             segments[1] |= 0x80
         self.write(segments)
+
+    def temperature(self, num):
+        if num < -9:
+            self.write([0x38, 0x3F]) # LO
+        elif num > 99:
+            self.write([0x76, 0x06]) # HI
+        else:
+            string = '{0: >2d}'.format(num)
+            self.write(self.encode_string(string))
+        self.write([0x63, 0x39], 2) # degrees C

tm1637_test.py

@@ -39,11 +39,8 @@
 # show "COOL"
 tm.write([0b00111001, 0b00111111, 0b00111111, 0b00111000])
 
-# all LEDs off
-tm.brightness(0)
-
 # all LEDs dim
-tm.brightness(1)
+tm.brightness(0)
 
 # all LEDs bright
 tm.brightness(7)
@@ -149,5 +146,12 @@
 # show "12:59"
 tm.numbers(12,59)
 
-# show temperature
-tm.temperature(24)  '24*C'
+# show temperature '24*C'
+tm.temperature(24)
+
+# show temperature works for range -9 to +99
+tm.temperature(-10) # LO*C
+tm.temperature(-9)  # -9*C
+tm.temperature(5)   #  5*C
+tm.temperature(99)  # 99*C
+tm.temperature(100) # HI*C