Casio WK-1500 manual Digital Signal Processor LSI11 HG51B155FD-1

CPU (LSI14: HD6433294A19F)

The 16-bit CPU contains a 32k-bit ROM, a 1k-bit RAM, seven 8-bit I/O ports, an A/D convertor and MIDIl interfaces. The CPU accesses to the working storage RAM, the DSP and the key touch LSI. The CPU interprets MIDI message using the working storage RAM. The CPU also controls buttons and LEDs. The following table shows the pin functions of LSI14.

Pin No.	Terminal	In/Out	Function
1	P50/TXD	Out	MIDI signal output
2	P51/RXD	In	MIDI signal input
3	P52/SCK	Out	Reset signal output
4	-RESET	In	Reset signal input
5	-NMI	In	Power ON trigger signal input
6	VCC	In	+5 V source
7	-STBY	In	Standby signal input. Connected to +5 V.
8	VSS	In	Ground (0 V) source
9, 10	XTAL, EXTAL	In	20 MHz clock input
11, 12	MD1, MD0	In	Mode selection input
13	AVSS	In	Ground (0 V) source
14	P70	In	Analog input terminal for the pitch bend wheel
15 ~ 21	P71 ~ P77	Out	Input terminals from keys (KI1 ~ KI7)
22	AVCC	In	+5 V source
23 ~ 30	P60 ~ P67	Out	LED drive signal output
31	VCC	In	+5 V source
32 ~ 48	A0 ~ A15	Out	Address bus
40	VSS	In	Ground (0 V) source
49 ~ 56	D0 ~ D7	In/Out	Data bus
57	P40	Out	Clock for KO signal generator
58	P41	Out	KO signal data
59	P42	Out	APO signal output
60	P43	Out	Read enable signal output
61	P44	In	Write enable signal output
62	P45	—	Not used
63	P46	Out	10 MHz clock output
64	P47	—	Not used. Connected to +5 V source.

DIGITAL SIGNAL PROCESSOR (LSI11: HG51B155FD-1)

Upon receipt of note numbers and their velocities, the DSP reads sound and velocity data from the sound source ROM in accordance with the selected tone; the DSP can read rhythm data simultaneously when a rhythm pattern is selected. Then it provides 16-bit serial signal containing data of the melody, chord, bass, and percussion to the DAC. When an effect selected, the DSP adds the effect to the sound data using a 256k-bit RAM.

The following table shows the pin functions of LSI11.

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