Casio CTK-611 Service Manual page 8

CPU (LSI1: UPD913GF-3BA)
The 16-bit CPU contains a 1k-byte RAM, three 8-bit I/O ports, two timers, a key controller and serial interfaces.
The CPU detects key velocity by counting the time between first-key input signal FI and second-key SI from
the keyboard. The CPU reads sound data and velocity data from the sound source ROM in accordance with
the selected tone; the CPU can read rhythm data simultaneously when a rhythm pattern is selected. Then the
CPU provides 16-bit serial sound data to the DSP. The CPU also controls MIDI input/output and stores
sequencer data into the working storage RAM.
The following table shows the pin functions of LSI1.
Pin No. Terminal
1 TXD0
2 RXD0
3 SCK0
4, 5 TXD1, RXD2
6 SCK1
7 AVCC
8 AN0
9 AN1
10 AGND
11 BCK
12 SO
13 LRCK
14 GND
15, 16 XLT0, XLT1
17 VCC
18, 19 MD0, MD1
20 RSTB
21 NMI
22 INT/P10
FI0 ~ FI3
23 ~ 30
SI0 ~ SI3
31 ~ 38 KC0 ~ KC7
FI4 ~ FI7
39 ~ 46
SI4 ~ SI7
FI8, FI9
47 ~ 50
SI8, SI9
51 FI10
52 SI10/P23
53 ~ 55 KI0 ~ KI2
56 MWNB
57 ~ 76 MA0 ~ MA17
77 MCSB0
78 MCSB1
79 MCSB2
In/Out
Out MIDI signal output
In MIDI signal input
Out APO (Auto Power Off) signal output
In/Out Data bus for the LCD driver
Out 1 MHZ synchronizing pulse output
In DVDD (+5 V) source
AC adaptor detection terminal.
+5 V when the keyboard is powered by batteries and becomes
In
0 V to cancel the APO function when AC adaptor is connected.
— Not used. Connected to ground.
In Ground (0 V) source
Out Bit clock output
Out Serial sound data output
Out Word clock output
In Ground (0 V) source
In/Out 20 MHz clock input/output
In +5 V source
In Mode selection terminal
In Reset signal input
In Power ON signal input
In/Out Data bus for the LCD driver
In Terminal for key input signal
Out Terminal for key scan signal
In Terminal for key input signal
— Not used
In Terminal for button input signal
Out Chip enable signal for the LCD driver
In Terminal for button input signal
Out Write enable signal for the DSP
Out Address bus
Out Chip enable signal output for the sound source ROM
Out Not used
Out Chip enable signal output for the DSP
— 6 —
Function