— 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
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