Table of Contents
Advertisement
2-3-7 Operation board
The operation board consists of key switches, LEDs and 7-segment LED. The lighting of LEDs is determined by scan
signals (SCAN0N to SCAN5N) and LED lighting selection signals (LED0N to LED7N) from the main board. The key
switches operated are identified by the scan signals (SCAN0N to SCAN5N) and the return signals (KEY0N to KEY2N).
As an example, to light "L1", the LED lighting selection signal (LED0N) should be driven low in synchronization with a low
level on the scan signal (SCAN0N). LEDs can be lit dynamically by repeating such operations.
As another example, if "K2" is pressed, the corresponding key switch is turned on feeding the low level of the scan signal
(SCAN1N) back to the main board via the return signal (KEY0N). The main board locates the position where the line
outputting the scan signal and the line inputting the return signal cross, and thereby determines which key switch was
operated.
Main board
KEY2N
YC1-17
KEY1N
YC1-16
KEY0N
YC1-15
SCAN5N
YC1-14
SCAN3N
YC1-13
SCAN4N
YC1-12
SCAN2N
YC1-11
YC1-10
SCAN0N
YC1-9
LED7N
YC1-8
LED6N
YC1-7
LED5N
YC1-6
LED4N
YC1-5
LED3N
YC1-4
LED2N
YC1-3
LED1N
YC1-2
LED0N
YC1-1
Figure 2-3-12 Operator board circuit block diagram
Operation board
Key switches
K11
K12 K13 K14
K15
K6
K7
K8
K9
K10
K1
K2
K3
K4
K5
D1
D2
D3
D4
L8
L17
L26
L7
L16
L25
L6
L15
L24
L5
L14
L23
L4
L13
L22
L3
L12
L21
L2
L11 L19
L20
L1
L10
L18
LEDs
D5
7-segment
LED
2DC
2-3-13
Advertisement
Table of Contents
