Composing Happy Birthday song

Composing Happy Birthday song

As a composing example program we present Listing 1, the familiar Happy Birthday song composition. Figure 1 is the corresponding circuit for it. To decorate the birthday atmosphere, two LEDs are turned ON/OFF alternately in program.

Figure 1. Song Example Circuit

Just as for any song composing, we need to write the music note subroutines for each note that will be used in song. The basic idea on note creation is the same as described for 440 Hz music tone: find the note's frequency, then calculate its half period T/2; then drive the speaker High or Low in such half period.

For example, in the 784 Hz "G5" tone subroutine, T/2 = 638 us, so the speaker needs to be driven High for 638us, then Low for 638us, and so on. To count this time, we utilize the ATtiny11's timer interrupt. This 8-bit timer is an up counter, it increases its count every clock cycle (that is 1 microsecond), when reaching count=256, it overflows to zero and generates an interrupt, and then increases one count per us again. Each interrupt causes the MCU to execute its interrupt service routine, in this case (see Listing 3) it is TIMOVF.

Instead of letting the timer count from zero, we set it start at 240, so the timer will overflow each 16 us. This is equivalent to every 16 us the timer has a "tick." Therefore for T/2=638 us, the needed Ticks# = 638/16=40.

Each music note takes some time to play. So the above half period High/Low must be repeated a number of times. We appropriately choose this number as 150. This number was proved appropriate by experiment. You can change it if you found it too short or too long.

After writing all note subroutines, the last step is to call these notes to form a song, as shown in the main program of Listing 3. Of course, you need to listen to it, then change it by your feeling, and do this for several iterations until you get the satisfactory music.

LISTING 1. Birthday Song program

;BDay.ASM(.bin 466 bytes) BirthDay Song with Flashing LEDs

.include "TN11def.inc" ; Port definitions here

.cseg

.org 0

rjmp RESET

RETI

rjmp TIMOVF

RESET:

ldi r16, $80

out SREG, r16 ; Enable any Int

ldi r16, $02

out TIMSK, r16 ; Enable Timer0 Int

ldi r16, $01

out TCCR0, r16 ; TimerControl: CK=>trig

sbi DDRB, 4 ; config DDRB bit-4 as output

sbi DDRB, 1 ; config DDRB bit-1 as output

sbi DDRB, 0 ; config DDRB bit-0 as output

AGAIN:

;----------------------------------*

cbi PORTB, 0 ; RLED=ON

Sbi PORTB, 4 ; GLED=OFF

in R4, PORTB

COM R4

out PORTB, R4 ; complement PortB bits

rcall Sew

rcall DLms

rcall Sew

rcall DLms

rcall La

rcall Sew

rcall Dos

rcall Tea

rcall DLhalfS

;----------------------------------*

in R4, PORTB

COM R4

out PORTB, R4 ; complement PortB bits

rcall Sew

rcall DLms

rcall Sew

rcall DLms

rcall La

rcall Sew

rcall Rays

rcall Dos

rcall DLhalfS

;----------------------------------*

in R4, PORTB

COM R4

out PORTB, R4 ; complement PortB bits

rcall Sew

rcall DLms

rcall Sew

rcall DLms

rcall Sews

rcall Mes

rcall Dos

rcall Tea

rcall La

rcall DLhalfS

;----------------------------------*

in R4, PORTB

COM R4

out PORTB, R4 ; complement PortB bits

rcall Fars

rcall DLms

rcall Fars

rcall Mes

rcall Dos

rcall Rays

rcall Dos

rcall DLhalfS

rjmp AGAIN

;---------------------------------------------------------

;the delay = .? sec at 1 MHz

DLhalfS:

LDI R20, 2

calop:

LDI R19, 235

malop:

LDI R21, 235

LOP1:

DEC R21

brne LOP1

DEC R19

brne malop

DEC R20

brne calop

RET

;---------------------------------------------------------

;delay = .? msec at 1 MHz

DLms:

LDI R20, 155

LOPms:

DEC R20

brne LOPms

RET

;-----------------------------------------------------------

TIMOVF:

LDI R16, 240 ;\ initialize TCNT0=240

OUT TCNT0, R16 ;/ 256-16=240

inc r18 ; inc TickCount by 1

RETI

;-----------------------------------------------------------

; 784 Hz "G5" tone; T/2 = 638 us, Ticks# = 638/16=39.875=>40

Sew:

Gh:

CLR R17

REPETGh:

CLR r18 ; clear TickCounter

loopGh1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 40 ; if reach 40 Ticks, then jmp

brlo loopGh1

CLR r18 ; clear TickCounter

loopGh2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 40 ; if reach 40 Ticks, then jmp

brlo loopGh2

INC R17

cpi R17, 150

BRLO REPETGh

RET

;-----------------------------------------------------------

; 880 Hz "A5" tone; T/2 = 568 us, Ticks# = 568/16=35.5

La:

Ah:

CLR R17

REPETAh:

CLR r18 ; clear TickCounter

loopAh1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 36 ; if reach 36 Ticks, then jmp

brlo loopAh1

CLR r18 ; clear TickCounter

loopAh2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 35 ; if reach 35 Ticks, then jmp

brlo loopAh2

INC R17

cpi R17, 150

BRLO REPETAh

RET

;-----------------------------------------------------------

; 988 Hz "B5" tone; T/2 = 506 us, Ticks# = 506/16=31.625

Tea:

Bh:

CLR R17

REPETBh:

CLR r18 ; clear TickCounter

loopBh1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 32 ; if reach 37 Ticks, then jmp

brlo loopBh1

CLR r18 ; clear TickCounter

loopBh2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 31 ; if reach 36 Ticks, then jmp

brlo loopBh2

INC R17

cpi R17, 150

BRLO REPETBh

RET

;------------------------------------------------------------

; 1047 Hz "C6" tone; T/2 = 478 us, Ticks# = 478/16=29.875=>30

Dos:

Cs:

CLR R17

REPETCs:

CLR r18 ; clear TickCounter

loopCs1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 30 ; if reach 30 Ticks, then jmp

brlo loopCs1

CLR r18 ; clear TickCounter

loopCs2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 30 ; if reach 30 Ticks, then jmp

brlo loopCs2

INC R17

cpi R17, 150

BRLO REPETCs

RET

;-----------------------------------------------------------

; 1175 Hz "D6" tone; T/2 = 426 us, Ticks# = 426/16=26.625

Rays:

Ds:

CLR R17

REPETDs:

CLR r18 ; clear TickCounter

loopDs1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 27 ; if reach 27 Ticks, then jmp

brlo loopDs1

CLR r18 ; clear TickCounter

loopDs2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 26 ; if reach 26 Ticks, then jmp

brlo loopDs2

INC R17

cpi R17, 150

BRLO REPETDs

RET

;-----------------------------------------------------------

; 1319 Hz "E6" tone; T/2 = 379 us, Ticks# = 379/16=23.6875

Mes:

Es:

CLR R17

REPETEs:

CLR r18 ; clear TickCounter

loopEs1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 24 ; if reach 24 Ticks, then jmp

brlo loopEs1

CLR r18 ; clear TickCounter

loopEs2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 23 ; if reach 23 Ticks, then jmp

brlo loopEs2

INC R17

cpi R17, 150

BRLO REPETEs

RET

;-----------------------------------------------------------

; 1397 Hz "F6" tone; T/2 = 358 us, Ticks# = 358/16=22.375

Fars:

Fs:

CLR R17

REPETFs:

CLR r18 ; clear TickCounter

loopFs1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 23 ; if reach 23 Ticks, then jmp

brlo loopFs1

CLR r18 ; clear TickCounter

loopFs2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 22 ; if reach 22 Ticks, then jmp

brlo loopFs2

INC R17

cpi R17, 150

BRLO REPETFs

RET

;------------------------------------------------------------

; 1568 Hz "G6" tone; T/2 = 319 us, Ticks# = 319/16=19.93=> 20

Sews:

Gs:

CLR R17

REPETGs:

CLR r18 ; clear TickCounter

loopGs1:

cbi PORTB, 1 ; PB1=LOW

cpi r18, 20 ; if reach 20 Ticks, then jmp

brlo loopGs1

CLR r18 ; clear TickCounter

loopGs2:

sbi PORTB, 1 ; PB1=HIGH

cpi r18, 20 ; if reach 20 Ticks, then jmp

brlo loopGs2

INC R17

cpi R17, 150

BRLO REPETGs

RET

;-----------------------------------------------------------

So far we only present three example program for the ATtiny11 application. But the list can go endless. It's only limited by everybody's capability and need.

Perhaps the most widely use for ATtiny11 is in chip music composing. Now that its price is so low, we won't have to care about how many chips we need. In this sense you can use as many ATtiny11 you need to build a "chip music library."