Casio CTK-750 manual Filter Block

Page 13

The following table shows the pin functions of the key touch LSI.

Pin No.

Terminal

In/Out

Function

 

 

 

 

1

REQB

Out

Interrupt request. Not used.

 

 

 

 

2, 3

FI10, SI10

In

Key input signal

 

 

 

 

4

VCC

In

+5V source

 

 

 

 

5

CRDB

In

Read enable signal

 

 

 

 

6

CWRB

In

Write enable signal

 

 

 

 

7

CCBB

In

Chip select signal

 

 

 

 

8, 9

T, STBY

In

Not used. Connected to +5V.

 

 

 

 

10

RESB

In

Reset signal

 

 

 

 

11

W

In

Not used. Connected to +5V.

 

 

 

 

12

CKI

In

10 MHz clock input

 

 

 

 

13, 14

TMD, TST

In

Not used. Connected to ground.

 

 

 

 

15

CKO

Out

Not used.

 

 

 

 

16

GND

In

Ground (0V) source

 

 

 

 

17

XIN

In

Not used. Connected to ground.

 

 

 

 

18

XOUT

Out

Not used.

 

 

 

 

19

TRES

In

Not used. Connected to ground.

 

 

 

 

20 ~ 23, 25 ~ 28

CD0 ~ CD7

In/Out

Data bus

 

 

 

 

24

GND

In

Ground (0V) source

 

 

 

 

29 ~ 31

CR0 ~ CR2

In

Address bus

 

 

 

 

32

VCC

In

+5V source

 

 

 

 

33 ~ 39, 41 ~ 43

FI0 ~ FI9,

In

Key input signal

53 ~ 55, 57 ~ 63

SI0 ~ SI9

 

 

 

 

 

 

40

VCC

In

+5V source

 

 

 

 

44 ~ 47, 49 ~ 52

KC0 ~ KC7

Out

Key scan signal

 

 

 

 

48, 56

GND

In

Ground (0V) source

 

 

 

 

64

VCC

In

+5V source

 

 

 

 

Filter Block

Since the sound signals from the DAC are stepped waveforms, the filter block is added to smooth the waveforms.

10V22µ-

+

To main volume

M5218APR

C104(H)

 

AVDD

 

 

 

2SC1740SQ

1K

1K

1K

C182(H)

C152(H)

1K

AG

AG

AG

AVEE

10K

10V22µ

From the DAC

— 11 —

Image 13
Contents CTK-750 Contents General SpecificationsElectrical Replacing the DSP HG51A115A01FDUPD6376CX Block DiagramKey Matrix Circuit DescriptionNomenclature of Keys Reset CircuitButton Matrix MidiPin No Terminal In/Out Function CPU HD6433298A18PGate Array UPD65005C-578 Digital Signal Processor HG51A115A01FD Block diagram of DSP and DAC circuit Key Touch LSI HG52E35P Filter Block Power Supply Circuit Power Amplifier LA4620Name Voltage For operation AvddM5712-CN1M Wiring DiagramMajor Waveforms Page PCB View and Major Check Points Schematic Diagrams Console PCB M5712-CN1M Keyboard PCBs M615T-KY1M, KY2M Exploded View S8053ANO IC Lead Identification and Internal DiagramM5218APR PC900VEB C E Q2 2SD1762E,F Q4 2SB1274Be C B Parts List N N FOB Japan Code No Parts Name Specification Yen Unit Price Lower Case Screws MA0300941A