Toshiba H1 Series - Manual (Page 595)

TMP92CZ26A
92CZ26A-592
3.22.3 Operational Description
3.22.3.1 Melody generator
The Melody function generates signals of any frequency (4Hz-5461Hz) based on
low-speed clock (32.768KHz) and outputs the signals from the MLDALM pin.
By connecting a loud speaker outside, Melody tone can easily sound.
(Operation)
At first, MELALMC have to be set as “1” in order to select melody waveform
as output waveform from MLDALM. Then melody output frequency has to be set to 12-bit
register MELFH, MELFL.
Followings are setting example and calculation of melody output frequency.
(Formula for calculating of melody waveform frequency)
@fs
= 32.768 [kHz]
Melody output waveform f MLD [Hz]
= 32768/ (2 × N + 4)
Setting value for melody N
= (16384/ f
MLD
)
− 2
(Note: N = 1~4095 (001H~FFFH), 0 is not acceptable)
(Example program)
In case of outputting “A” musical scale (440Hz)
LD (MELALMC),
−−XXXXX1B ; Select
melody waveform
LD (MELFL), 23H ; N = 16384/440 − 2 = 35.2 = 023H
LD (MELFH), 80H ; Start to generate waveform
(Refer: Basic musical scale setting table)
Scale Frequency
[Hz]
Register
Value: N
C 264 03CH
D 297 035H
E 330 030H
F 352 02DH
G 396 027H
A 440 023H
B 495 01FH
C 528 01DH