SM1126 Series

NIPPON PRECISION CIRCUITS—12

Melody words

Melody words contain all the information needed for playback of a single note, including the note duration

and type (name or rest). Each melody word comprises a 3-bit length code (R2 to R0) followed by a 5-bit type

code (S4 to S0).

End word

The end word (01011111) indicates the end of the melody. When the end word is detected during melody

playback, operation returns to the SRAM leading address. All data in SRAM after the end word is ignored.

End-of-write command

The end-of-write command (10111111) is used to return to play mode from write mode. This command

should be executed when power is first applied to set play mode.

Figure 12. Melody word timing

Figure 13. End word timing

Figure 14. End-of-write command timing

SIO

SC

ST

ADDRESS

(n)th data

n

n-1

write (n-1)th Data

write (n)th data

n+1

(n-1)th data

SIO

SC

ST

01

ADDRESS

0

1

1

111

next word

m+1

m

write END-WORD

write next word

m+2

SIO

SC

ST

WRITE mode changed to PLAY mode

01

11

1

1

1

1