— 7 —
DIGITAL SIGNAL PROCESSOR (LSI2: HG51B227FB-1)
The DSP receives 16-bit serial sound data output from the CPU and adds the selected effect to the sound data
using the effect RAM. Then the DSP provides the sound data to the DAC. The DSP also controls button input/
output.
The following table shows the pin functions of LSI2.
Pin No.
Terminal
In/Out
Function
80
VCC
In
+5 V source
81
GND
In
Ground (0 V) source
82
MRDB
Out
Read enable signal output for the sound source ROM
83 ~ 98
MD0 ~ MD15
In/Out
Data bus
99
PLE
Out
Reset signal output for the DSP
100
P17
In/Out
Data bus for the LCD driver
Pin No.
Terminal
In/Out
Function
1 ~ 3, 80
PB0 ~ PB3
In
Button input terminals
4
PB4
In
ASSIGNABLE Jack input
5
SO
Out
Serial sound data output for the DAC
6
WCKO
Out
Word clock output for the DAC
7
VDD3
In
+5 V source
8
TEST
—
Not used
9
RESB
In
Reset signal input
10
VSS2
In
Ground (0 V) source
11, 12
XIN, XOUT
In/Out
20 MHz clock input/output
13
WCKI
In
Word clock input from the CPU
14
SI
In
Serial sound data input from the CPU
15
BCKI
In
Bit clock input from the CPU
16
SINC
In
1 MHz synchronizing pulse input
17
VDD2
In
+5 V source
18 ~ 25
IO0 ~ IO7
In/Out
Data bus
26
RCEB
Out
Chip enable signal output for the working storage RAM
27
VSS3
In
Ground (0 V) source
28
AD1
In
Address bus
29
OEB
Out
Output enable signal for working storage RAM
30
WEB
In
Write enable signal
31
VDD3
In
+5 V source
32
CE2
In
Chip enable signal input. High active.
33
AD0
In
Address bus
34
CE1B
In
Chip enable signal input. Low active.
35 ~ 41, 43
EIO0 ~ EIO7
In/Out
Data bus for the effect RAM
MC-Service
