Rohm BU7858KN, Technical Note

Page: 20 / 25

20/24
【 BU7893GU 】
SAMPLE# AUDIO PATH+ AUDIO DAC BLOCK SETTING SEQUENCE
After powering up and canceling reset, set paths according to the sequence shown as below:
(1) Start up reference voltage
Start up the reference voltage in the REF_PWR register (00h).
To start up the VREF block fast, set the REF_ON bit (bit-0) and BST_ON bit (bit-1) to "1" simultaneously. After starting
up the reference voltage startup, set just the BST_ON bit (bit-1) to "0".
(2) Start up Audio DAC
When using Audio DAC
(2-1) Enable PLL block clock input and start up PLL
Start up the power supply of the PLL and enable clock input to the PLL in the PLL_PWR
register (16h).
Set REF1_ON (bit-1) and PLL_ON (bit-0) to "1" simultaneously.
(2-2) Caution concerning interim between starting up PLL block and starting up Audio DAC block
After starting up the power supply of the PLL in the PLL_PWR register (16h), wait 10 msec before starting up the
Audio DAC.
(2-3) Start up Audio DAC block
Start up the power supply of the Audio DAC in the DAC SET4 register (13h).
Set DAC_ON (bit-5) and DAC_RSTB (Bit-4) to "1".
(2-4) Set 3D surround and Equalyzer parameter
Please tell us about the parameter setting when you use this function.
(3) Start up analog input amplifier to use
Start up the power supply of the input amplifier and input volume in the IAMP_PWR register (01h).
(4) Set input volume
Set the input volume in the IVR_1 register (09h).
(5) Set mixing path
Make mixing path settings in the MIX1 register (02h), MIX2 register (03h), MIX3 register (04h), and MIX4 register (05h).
(6) Set startup noise reduction sequence
Set the sequence time in the POP_TM register (07h).
(7) Set click noise reduction sequence
Set the sequence time in the OVR_TM register (0Ah).
(8) Set output path
Enable the relevant output path in the PATH_CNT register (06h).
(9) Set output volume
Set output volume values =0x18(-48dB) in the OVR_1 register (0Bh).
(10) Ramp up output driver amplifier
Ramp up the output driver amplifier in the DRV_PWR register (08h).
(11) Caution concerning interim between ramping up output driver amplifier and canceling mute
After setting the DRV_PWR register (08h), wait the sequence time set in the POP_TM register (07h) before canceling
mute.
(12) Cancel mute
Cancel mute state of the output driver amplifier in the DRV_MT register (0Ch).
(13) Caution concerning interim between canceling mute and setting output volume
After setting the DRV_MT register (0Ch), wait the sequence time that is set in the OVR_TM register (0Ah) before
subsequently setting output volume.
(14) Set output volume
Set output volume values in the OVR_1 register (0Bh).