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TDA7468 volume control

Question asked by ferguson.ellis on Oct 3, 2013
Latest reply on Feb 18, 2014 by zhao.yuntao
Hello! i have a trouble with setting volume level in TDA7468. I use a wiring diagram as datasheet, and send setting to this IC using the C code:
void writer(unsigned char adr_IC, unsigned char adr_reg,unsigned char data)
{
i2c_start();
i2c_write(adr_IC);
i2c_write(adr_reg);
i2c_write(data);
i2c_stop();
delay_ms(50);
}
writer (0x88,0x00,0x00); // input=in1
writer (0x88,0x01,0x00);// input gaine=0 dB
writer (0x88,0x02,0x00); // surround=off
writer (0x88,0x03,0x00);// left volume=0dB maximum
writer (0x88,0x04,0x00);// right volume=0dB maximum
writer (0x88,0x05,0x77); //bass & treble = 0dB
writer (0x88,0x06,0x01); // MUTE=off
writer (0x88,0x07,0x00); // bass ALC=OFF


but the level of the output signal is significantly lower than the input signal. chip reacts to further change the tone level and volume level to down. please, explain how to set the volume level

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