Specifications

I-92 EPSON S1C62N82 TECHNICAL HARDWARE
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Melody Generator)
Melody data
• Melody ROM
The melody ROM has an 128-word capacity, the length of
a word being 10 bits. Basically, data of 1 note is stored
in 1 word. These data are continuously read out by the
hardware and melody is played. The 4 types of data
which may be written as 1-note data are as follows:
(1)Interval data
(2)Note data
(3)End data
(4)Attack data
When melody playing starts, the start address is specified
with the address written on the address register. The
melody ROM address is then automatically increased by
the address counter one step at a time and melody is
played. The melody automatically stops at the point
where the end-of-melody data written on the melody ROM
is read out by the hardware. At the same time, interrupt
flag is set and interrupt for the CPU is generated.
Fig. 4.11.14
Data format of
the melody ROM
Since only melody
D8 D7 D6 D5 D4 D3 D2 D1 D0
Note data Scale data
End
data
D9
Attack
data
start address setting and melody start control may be
controlled by software, optional melodies which have
been written on the melody ROM can easily be played by
lessening the load of the software.
The format of the data contained in a melody ROM word
is shown in Figure 4.11.14. These melody data are
explained in details below.