2-wire LCD, pushbuttons and speaker/buzzer 74LS164

[Theo]

Based on the 2-wire lcd diagram from Myke Predko with mods(74ls164) from Mike McLaren (See link); some functions for the using off push buttons or switches and a speaker/buzzer, see the diagram.
Very useful for those who would like to play with microcontrollers with less pins.

The variable Button gets the value of 1 to 15; pushing button A = 1, B = 2, C = 4, D = 8.
By pushing 2 or more buttons at the same time you will get the sum of those buttons.

To use the simple speaker or buzzer: it needs to be activated every time by the function BuzzerOn, followed by Tone YY,ZZ

http://www.electro-tech-online.com/threads/k8lh-breadboard-buddy-lcd-interface.92030

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#chip mega8,8

'Use LCD in 2 pin mode with 74LS164 / 74HC164
#define LCD_IO 2
#define LCD_DB PORTC.0 ; databit
#define LCD_CB PORTC.1 ; clockbit
#define LCD_NO_RW

#define SWX PORTC.2 ; input pin from pushbuttons (A,B,C,D)
#define Led PORTC.5 ; output pin for led
#define SoundOut PORTC.0 ; output pin for tone

dir SWX in ; set port as input

BuzzerOn
tone 440,50 ; Beep
tone 660,50
tone 880,50
tone 1350,100

do
PushButton
locate 0,0
print "Button= ": print Button:print " "
pulseout Led, 1 Ms ; if active: program is running
loop

; ---------------------- Functions -----------------------
function PushButton
ClockXXTimes(8) ; clock in 8 times zero for clearing shiftreg
ClockIn1 ; clock in a 1 to activate pin 3 (74LS164)
button=0:GPVar=1
repeat 4 ; clock 4 times to activate resp. pin 4, 5, 6 (74LS164)
if SWX then
wait 10 mS ; debounce switches/buttons
end if
if SWX then ; check for A,B,C and/or D button(s)
button = button OR GPVar ; set 1 bit only, so pushing two or more buttons at
end if ; the same time will be shown in the variable button
rotate GPVar left ; shift bit to the left (1,2,4,8)
set LCD_CB on:set LCD_CB off ; clock 1 time
end repeat
ClockXXTimes(3) ; clear shiftreg
end function

function ClockXXTimes(in GPVar) ; clock in XX times zero
set LCD_DB off
for index = 1 to GPVar
set LCD_CB on:set LCD_CB off
next
end function

function ClockIn1 ; clock in one
set LCD_DB on:set LCD_CB on:set LCD_CB off:set LCD_DB off
end function

function BuzzerOn
ClockXXTimes(8) ; clock in 8 times zero for clearing shiftreg
ClockIn1 ; clock in one and
ClockXXTimes(6) ; clock in 6 times zero to activate pin 12 (74ls164)
end function

[Theo]

Diagram

[Anobium]

Nice job! And, great documentation.