用basic语言编写的时钟-百合电子工作室

介绍：

这个制作有点逗。
有趣之一它是使用一台坏仪表的米字管来作显示；
有趣之二是计时的频率用交流的60Hz(国内是50Hz)；
有趣之三是用Basic语言编写的。(终于见识到开发AVR的第三种语言了)。

实物图：

电路图：(点击可以放大)

源代码如下：

' Andy Maxwell
' A 12-hour clock driven by 60hz from the wall.
' 13 Feb 2002
' Going to drive some numitron tubes in a scale head
' I found at a a government surplus place.
' Made for Royal Hutchinson because it's so perfect for his office
' BASCOM-AVR basic source for the Atmel 90AT2313 microcontroller
' Also, there is a 7404 inverter with a diode to clean up
' the 60hz from a 9v AC input.
' the 9vAC is from an old TRS-80 powersupply I opened up,
' took out the 1/2-wave rectifier and capacitor, left the fuse in,
' and closed back up.
' The input for the 7404 is taken from before the rectifier/7805
' powersupply, with a signal diode pointing back towards the powersupply
' and connected to an input.
Dim Clock_t As Integer ' count ticks for a hole second
Dim Clock_s As Byte ' seconds
Dim Clock_m As Byte ' Minutes
Dim Clock_h As Byte ' hours
' A flag to alert when a new second has passed
Dim Clock_newsec As Bit
' This cycles at 120Hz (set on each transition from high to low)
Dim Clock_ticker As Bit
' last level of the 60Hz input, used to determine when it changes
Dim Lastlevel As Bit
' clear the clock.
Clock_h = 0
Clock_m = 0
Clock_s = 0
Clock_t = 0
' this is a temp variable
' that will hold the hour in either 12 or 24-hour format
' used by the display
Dim Temp_h As Byte
' variables for the display routine
Dim Tempstr As String * 4
Dim Y As Byte
Dim Z As Byte
Dim Tempbyte As Byte
' This one holds which digit is being shown right now
Dim Digit As Byte
' what goes out to the Numitron tubes
Dim Fourdigitdisplay As String * 4
' Okay, set all of port B (pins 12 - 19) to high
Ddrb = &B11111111
' ------
' Here's stuff to set the clock with
'
' Minutes
' set the pin to be an input
Reset Ddrd.4
' If you set a pin to be an input and set the output to be 1
' it turns on the internal pullup
Set Portd.4
' Hours
' set the pin to be an input
Reset Ddrd.5
' internal pullup
Set Portd.5
' diagnostic output
' no longer used
' Set Ddrd.3
' Reset Portd.3
' Military time switch
' set the pin to be an input
Reset Ddrd.2
' If you set a pin to be an input and set the output to be 1
' it turns on the internal pullup
Set Portd.2
' --- 60Hz square wave (cleaned up by the 7404)
' set this guy to be an input,
Reset Ddrd.6
' no pullup resistor
Reset Portd.6
Reset Lastlevel
' *** Main Program Loop
Do
' See if the 60Hz input is different from the last time
' we came through
If Lastlevel <> Pind.6 Then
' We have a state change in the AC
' Set the ticker so the clock subroutine can do it's gig
' and toggle Lastlevel so we can notice it next time
Toggle Lastlevel
Set Clock_ticker
'Toggle Portd.3 ' Diagnostic 60hz output
End If
' Go check to see if it's a new second, and update all the
' clock_? variables.
Gosub Check_clock
' This is the hour value. Fine if we're in 24-hour military mode
Temp_h = Clock_h
If Pind.2 = 0 Then
' we are in 12-hour mode
' figure out what the 12-hour equivelent is
Temp_h = Clock_h
If Temp_h > 12 Then
Temp_h = Temp_h - 12
End If
' there ain't no zero hour in normal 12-hour clocks
' I didn't realize this until I started building
' a Nixie clock and Michele pointed it out.
If Temp_h = 0 Then
Temp_h = 12
End If
End If
' format the display. pad with zeros,
' and concatenate the hours and minutes
Fourdigitdisplay = Format(str(temp_h) , "00") + Format(str(clock_m) , "00")
'' ************ Start OF DISPLAY CODE
' each pass through the main do loop, show a different digit
Incr Digit
' wrap around if it's 4.
If Digit = 4 Then : Digit = 0 : End If
' add 1 to the digit count 'cause MID is 1 based
Y = Digit + 1
' and get the digit that we want
Tempstr = Mid(fourdigitdisplay , Y , 1)
' Okay, this is confusing, so pay attention.
' The low nibble (4-bits) of portb is connected to the 7448
' 7-segment display driver on the old display subboard
' Send it Binary Coded Decimal (BCD) and it lights up the right
' segments on all the lit tubes. That's the val(tempstr) you see.
'
' The high nibble of portb is connected to the switching
' transistors that power the individual digits.
' So, we want to power-up digit 1, and send BCD for digit 1
' To get just one line high, I raise 2 to the Digit power
' and get 1, 2, 4, or 8 (check it out in binary)
' then I multiply it by 16 to shift it up to the high nibble.
'
' Then, I add the BCD value of the digit to set the low nibble
'
' Trust me, it works.
Tempbyte = 2 ^ Digit ' and light up the one line for the common cathode
Tempbyte = Tempbyte * 16 ' move it up to the high nibble
Tempbyte = Tempbyte + Val(tempstr) ' add low byte number..
' and send it to portb (pins 12-19)
Portb = Tempbyte
'' ************ END OF DISPLAY CODE
' this is left over from the serial testing
'Print Clock_h ; ":" ; Clock_m ; ":" ; Clock_s ; ":"
' **** CLOCK SETTING ***
' Now, this is the clock setting routine
If Clock_newsec = 1 Then
' we've got ourselves a new second!
' clear the flag.
Reset Clock_newsec
' see if they've pressed the Minute set button
If Pind.4 = 0 Then
' if so, increment the minute counter
Incr Clock_m
' reset the seconds
Clock_s = 0
' if we're over 60 minutes, set it back to zero
If Clock_m = 60 Then Clock_m = 0
End If
'ditto for the hours button
If Pind.5 = 0 Then
Incr Clock_h
Clock_s = 0
If Clock_h = 24 Then Clock_h = 0
End If
End If ' clock_newsec = 1
Loop ' go back to the loop
'---------------------------------------
Check_clock:
'---------------------------------------
'output: Clock_t,h,m,s
If Clock_ticker = 0 Then
' we haven't seen a change in the 60Hz line
Return
End If
' If we're here, we have seen a change in the 60hz line
' either up or down
' reset the flag so we'll notice it next time
Reset Clock_ticker
' and increment the sub counter
Incr Clock_t
' this is 120Hz because it's counting -transitions-.
' the up and the down of the 60hz wave each count as one
If Clock_t = 120 Then
' Woo! It's been a full second!
Clock_t = 0
' this is the flag for the time setting routine
Set Clock_newsec
' Now, increment each unit counter by one and see if we've overflowed
' TICK
Incr Clock_s
' Did we overflow the seconds?
If Clock_s = 60 Then
' reset the seconds to zero
Clock_s = 0
' and bump up the minutes counter
Incr Clock_m
' and so forth...
If Clock_m = 60 Then
Clock_m = 0
Incr Clock_h
If Clock_h = 24 Then
Clock_h = 0
' here are all the end ifs from the incrementers
End If
End If
End If
End If
' and return to the main loop
Return
' **** END OF PROGRAM