Specifications

I-76 EPSON S1C62N82 TECHNICAL HARDWARE
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Melody Generator)
A detailed description of the circuits which form the melody
generator is provided below.
(a)Frequency booster
The configuration of the frequency booster is shown in
Figure 4.11.2. It is a circuit which raises the input
frequency (32,768 Hz) for the melody generator to 2 times
the frequency. The output of this frequency booster is
provided with a switch through the mask option; by
selecting this switch, scale which can be output may be
changed. In other words, if frequency booster output
were selected for input to interval generating circuit,
interval can be created between C4 to C7
#
and if 32,768
Hz were selected as is, interval can be created between
C3 to C6
#
.
Fig. 4.11.2
Frequency booster
Booster
32,768 Hz
To interval
generating circuit
(b)Controller
The configuration of the controller is shown in Figure
4.11.3. The controller consists of a 4-bit register located
in the I/O RAM space and an ON/OFF control circuit and
controls the melody's ON/OFF, tempo selection, playing
speed selection. The ON/OFF control circuit controls the
turning ON/OFF of the melody playing by entering the
MELC register output and the signal from the end-of-
melody signal generator. The address of the 4-bit register
is "0F2H" and the meaning of each bit is as follows:
D0 (MELC):
This is the bit that controls the turning ON/OFF of the
melody playing. The controlling function of this bit
makes it possible to control the above-described 3
types of playing. Refer to "Playing mode" regarding the
method of control.