Yamaha A-S201 Service Manual page 31

Key detection for A/D port
Key input (A/D) pull-up resistance 10 k-ohms
0 Ω + 1.0 kΩ + 1.0 kΩ
Detected voltage value
0 – 0.22 V 0.23 – 0.64 V 0.65 – 1.06 V 1.07 – 1.55 V 1.56 – 2.09 V 2.10 – 2.62 V 2.63 – 3.12 V
at 40 pin
A/D value
000 – 011 012 – 032 033 – 054
(3.3 V = 255)
INPUT INPUT TREBLE
KEY0
+
+ 7.5 kΩ + 15 kΩ
Detected voltage value
2.08 – 2.41 V 2.42 – 2.77 V
at 41 pin
A/D value
161 – 187 188 – 214
(3.3 V = 255)
SPEAKER SPEAKER
KEY1
A B
Destination detection for AD port
Pull-up resistance 10 k-ohms
R280
20 kΩ 6.2 kΩ 7.5 kΩ
on MAIN (1) P.C.B.
Detected voltage value
2.1 – 2.3 V 1.19 – 1.32 V 1.33 – 1.48 V 0.4 – 0.61 V 0.62 – 0.76 V 1.49 – 1.59 V
at 45 pin
A/D value
162 – 178 092 – 102 103 – 114
(3.3 V = 255)
Destination R T K
+ 1.5 kΩ + 2.2 kΩ + 3.3 kΩ + 4.7 kΩ
055 – 079 080 – 107 108 – 134 135 – 160
TREBLE BASS BASS PURE
– + – DIRECT
1.8 kΩ 2.7 kΩ 9.1 kΩ
031 – 047 048 – 059 115 – 123
A G (B, G) L
A-S201
31