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PT2258 CONTROL SOFTWARE PROCEDURE
1. In order to ensure exact operation under any operating voltage, it is recommended an instruction to
clear the register “C0H” must be transmitted first. Please refer to the following diagram:
Start 1 0 0 0 1 0 0 0 Ack
1
1
2258 Address
Clear Register
2. The PT2258 function register does not have any default settings. After clearing the register, an initial
value must send in order to each register. If a register does has not been set, it is possible that no
sound will be output.
3. When adjusting the volume of PT2258, it is necessary to send a multiple of 10dB followed by a 1dB
code to the attenuator in sequence. If this sequence is not followed, or if only a 10dB or 1dB value is
sent, the IC may not operate normally. Please refer to the diagram below:
Volume setting -42dB
Start 1 0 0 0 1 0 0 0 Ack 1 1 0 1 0 1 0 0 ACK 1 1 1 0 0 0 1 0 Ack
PT2258 Address
-40dB
Start 1 0 0 0 1 0 0 0 Ack 1 1 1 0 0 0 1 0 Ack 1 1 0 1 0 1 0 0 ACK
PT2258 Address
-2dB
The two methods above are both acceptable.
Warning!! The following transmission method is not permitted.
Send only a 10dB attenuation value:
Start 1 0 0 0 1 0 0 0 Ack
1
1
PT2258 Address
-40dB
Send only a 10dB attenuation value:
Start 1 0 0 0 1 0 0 0 Ack
1
1
PT2258 Address
-2dB
Do not send a 10dB code without simultaneously with a 1dB code or in combination with other
instruction codes.
Start 1 0 0 0 1 0 0 0 Ack 1 1 1 0 0 0 1 0 Ack 1 1 1 1 1 0 0 1 ACK 1 1 0 1 0 1 0 0 ACK Stop
PT2258 Address -2dB
PT2258 V1.2
- 9 -
July, 2005
6-Channel Electronic Volume Controller IC
PT2258
0
0
0
0
0
0
Ack Stop
Stop
-2dB
Stop
-40dB
0
1
0
1
0
0
ACK Stop
1
0
0
0
1
0
ACK Stop
All CH mute
-40dB