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AN #204 - LED Drive Control Special Circuit TM1637 |
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TM1637 is a kind of LED (light-emitting diode display) drive control special circuit with keyboard scan interface and it's internally integrated with MCU digital interface, data latch, LED high pressure drive and keyboard scan.
Sample to show how to use 4 Digit LED Display from Catalex. Display is TM1637 based
Call TM1637_On --> turns display on and sets brightness to PWM 25%
Call TM1637_Off --> turns display off
Call TM1637_Disp (data) --> puts data on display !! The display shows any number from 0 to 9999. Larger values will display only the 4 least digits.
The programm is based on info on 'kaktus-website' http://kaktusa.pl/tm1637-w-module-z-wyswietlaczem-led-7seg-4-cyfry/
The datasheet can be downloaded HERE
The communication with the display is NOT I2C since the device has no slave-address so you can use also 'non-I2C'-pins
However keep in mind to use pull-ups. Users of the Catalex-board don't have to worry, The pull-ups are mounted on this board.
Example code:
$regfile = "m2560def.dat"
$crystal = 12000000
$hwstack = 100
$swstack = 100
$framesize = 100
Config Portf.0 = Output ' for TM1637 clock
Config Portf.1 = Output ' for TM1637 data
Tm1637_clk Alias Portf.0
Tm1637_dout Alias Portf.1
Tm1637_din Alias Pinf.1
Declare Sub Tm1637_disp(byval Bdispdata As Word) 'The display can only show numbers
Declare Sub Tm1637_wrbyte(byval Bdata As Byte)
Declare Sub Tm1637_on()
Declare Sub Tm1637_off()
Declare Sub Tm1637_start()
Declare Sub Tm1637_stop()
Declare Sub Tm1637_ack()
'========================================================================
'
' Start main
'
'========================================================================
Tm1637_on
Tm1637_disp 45
Wait 2
Tm1637_off
Do
Loop
End
'=========================================================================
'
' Subroutines
'
'========================================================================
Sub Tm1637_ack()
Reset Tm1637_clk
Waitus 5
Reset Tm1637_dout
Bitwait Tm1637_din , Reset
Set Tm1637_clk
Waitus 2
Reset Tm1637_clk
Set Tm1637_dout
End Sub
Sub Tm1637_off()
Tm1637_start
Tm1637_wrbyte &H80 'Turn display off
Tm1637_ack
Tm1637_stop
End Sub
Sub Tm1637_on()
Tm1637_start
Tm1637_wrbyte &H8A 'Turn display on and set PWM for brightness to 25%
Tm1637_ack
Tm1637_stop
End Sub
Sub Tm1637_start()
Set Tm1637_clk
Set Tm1637_dout
Waitus 2
Reset Tm1637_dout
End Sub
Sub Tm1637_stop()
Reset Tm1637_clk
Waitus 2
Reset Tm1637_dout
Waitus 2
Set Tm1637_clk
Waitus 2
Set Tm1637_dout
End Sub
Sub Tm1637_disp(byval Bdispdata As Word)
Local Bcounter As Byte
Local Strdisp As String * 5
Strdisp = Str(bdispdata)
Strdisp = Format(strdisp , " ")
Tm1637_start
Tm1637_wrbyte &H40 'autoincrement adress mode
Tm1637_ack
Tm1637_stop
Tm1637_start
Tm1637_wrbyte &HC0 'startaddress first digit (HexC0) = MSB display
Tm1637_ack
For Bcounter = 2 To 5
Select Case Asc(strdisp , Bcounter)
Case "0" : Tm1637_wrbyte &B00111111
Case "1" : Tm1637_wrbyte &B00000110
Case "2" : Tm1637_wrbyte &B01011011
Case "3" : Tm1637_wrbyte &B01001111
Case "4" : Tm1637_wrbyte &B01100110
Case "5" : Tm1637_wrbyte &B01101101
Case "6" : Tm1637_wrbyte &B01111101
Case "7" : Tm1637_wrbyte &B00000111
Case "8" : Tm1637_wrbyte &B01111111
Case "9" : Tm1637_wrbyte &B01101111
Case Else : Tm1637_wrbyte &B00000000
End Select
Tm1637_ack
Next
Tm1637_stop
End Sub
Sub Tm1637_wrbyte(byval Bdata As Byte)
Local Bbitcounter As Byte
For Bbitcounter = 0 To 7 'LSB first
Reset Tm1637_clk
Tm1637_dout = Bdata.bbitcounter
Waitus 3
Set Tm1637_clk
Waitus 3
Next
End Sub
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