TM1637

10 ''' 11 Abstraction of the 4 digit 7-segment display based on the TM1637 display driver. 12 7-bit ASCII characters are mapped as close as possible to the 7 display segments. If a 13 character cannot be mapped, the digit is cleared. 14 ''' 15 16 myData = [0,0,0,0] 17 18 @staticmethod

19 - def getDisplayableChars():

20 ''' 21 Returns a string with all displayable characters taken from PATTERN dictionary. 22 @return: The character set that can be displayed 23 ''' 24 s = "<SPACE>" 25 k = 33 26 while k < 127: 27 ch = chr(k) 28 if TM1637.PATTERN[ch] != 0: 29 s = s + ch 30 k += 1 31 return s

32 33 @staticmethod

34 - def toHex(intValue):

35 ''' 36 Returns a string with hex digits from given number (>0, any size). 37 @param number: the number to convert (must be positive) 38 @return: string of hex digits (uppercase), e.g. 0xFE 39 ''' 40 return '%02x' % intValue

41 42 @staticmethod

43 - def toBytes(intValue):

44 ''' 45 Returns a list of four byte values [byte#24-#31, byte#16-#23, byte#8-#15, byte#0-#7] of given integer. 46 @param number: an integer 47 @return: list with integers of 4 bytes [MSB,..., LSB] 48 ''' 49 byte0 = intValue & 0xff 50 byte1 = (intValue >> 8) & 0xff 51 byte2 = (intValue >> 16) & 0xff 52 byte3 = (intValue >> 24) & 0xff 53 return [byte3, byte2, byte1, byte0]

54 55 @staticmethod

56 - def toInt(hexValue):

57 ''' 58 Returns an integer from given hex string 59 @param number: a string with the number to convert, e.g. "FE" or "fe" or "0xFE" or "0XFE" 60 @return: integer number 61 ''' 62 return int(hexValue, 16)

63 64 # ------------------- Constructor ---------------------------------

65 - def __init__(self, dio = 38, clk = 40, lum = 4):

66 ''' 67 Creates a display instance that uses the two given GPIO pins for data (dio, default: 38) and 68 clock (clk, default: 40). 69 It is set to the given luminosiy (0..9, default: 4) 70 ''' 71 GPIO.setmode(GPIO.BOARD) 72 GPIO.setwarnings(False) 73 self.clk = clk 74 self.dio = dio 75 self.lum = lum 76 self.colon = False 77 self.startPos = 0 78 self.text = None 79 GPIO.setup(clk, GPIO.OUT) 80 GPIO.setup(dio, GPIO.OUT) 81 GPIO.output(clk, 0) 82 GPIO.output(dio, 0)

83 84 # ------------------- Public methods ---------------------------------

85 - def erase(self):

86 ''' 87 Clears the display (all digits are turned off). 88 ''' 89 self.colon = False 90 self.show(" ")

91

92 - def show(self, text, pos = 0):

93 ''' 94 Displays 4 characters of the given text. The text is considered to be prefixed and postfixed by spaces 95 and the 4 character window is selected by the text pointer pos that determines the character displayed at the 96 leftmost digit, e.g. (_: empty): 97 showText("AbCdEF") -> AbCd 98 showText("AbCdEF", 1) -> bCdE 99 showText("AbCdEF", -1) ->_AbC 100 showText("AbCdEF", 4) -> EF__ 101 @param text: the text to display (string or integer) 102 @param pos: the start value of the text pointer (character index positioned a leftmost digit) 103 ''' 104 self.startPos = pos 105 self.pos = pos 106 self.text = str(text) # digits to chars 107 if len(self.text) < 4: 108 self.text = "%-4s" % self.text 109 self._cropText()

110

111 - def scroll(self, text):

112 ''' 113 Starts scrolling the text to the left and blocks until all characters have passed by. 114 ''' 115 self.show(text) 116 sleep(1.5) 117 while self.toLeft() > 0: 118 sleep(1) 119 sleep(1)

120

121 - def toRight(self):

122 ''' 123 Scrolls the current text one step to the left by decreasing the text pointer. 124 @return: the number of characters hidden, but remaining to be displayed at the left (>=0); -1, if error 125 ''' 126 if self.text == None: 127 return -1 128 self.pos -= 1 129 self._cropText() 130 return max(0, 4 + self.pos)

131

132 - def toLeft(self):

133 ''' 134 Scrolls the current text one step to the left by increasing the text pointer. 135 @return: the number of characters hidden, but remaining to be displayed at the right (>=0); -1, if error 136 ''' 137 if self.text == None: 138 return -1 139 self.pos += 1 140 self._cropText() 141 nb = len(self.text) - self.pos 142 return max(0, nb)

143

144 - def toStart(self):

145 ''' 146 Shows the text at the start position by setting the text pointer to its start value. 147 ''' 148 if self.text == None: 149 return -1 150 self.pos = self.startPos 151 self._cropText()

152

153 - def setLuminosity(self, lum):

154 ''' 155 Sets the brightness of the display. 156 @param luminosity the brightness (0..9, 0: invisible) 157 ''' 158 self.lum = lum

159

160 - def setColon(self, enable):

161 ''' 162 Enables/disables the colon in the middle of the screen. 163 @param enable if True, the colon is shown in all subsequent text operations 164 ''' 165 self.colon = enable

Source Code for Module TM1637