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●Description of operations

＜

BU9253AS/FS＞

・

OSC(Oscillator)

Clock is generated by connecting external RC circuit. Clock is used for the delay counter.

・

Mute control circuit (MUTE)

By input voltage of the mute terminal, 3 statuses, that is, mute, mute release (operating), and clock stop & mute can be

selected.

・

COUNTER

This counter is for generating delay time. It can generate delay time about 131ms at oscillation frequency

Fclk = 375kHz.

・

SRAM

SRAM with 8Kbit capacity for generating the delay.

・

A/D side LPF operation amplifier

LPF can be structured by external RC, and band limit of signal to be input to A/D is available.

・

A/D

This digitalizes output signal of AD side LPF, and outputs it to SRAM.

・

D/A side LPF operation amplifier

LPF can be structured by external RC, and band limit of signal to be output to D/A is available.

・

D/A

This converts delayed audio digital data input from SRAM into analog signal.

・

Mixing amplifier (MIX)

This circuit is used for mixing delayed signals and (original sound) signals input from MIX IN.

＜

BU9262AFS＞

・

Serial control circuit

This serial I/F circuit is for setting each register. It can be controlled by serial 16bit data. It reads in SI at the rise of SCK,

and latches data at the rise of SLT.

No.

Mode

Remarks

D0

D1

D2

Delay time

Delay time setting

"Refer to the separate table."

D3

D4

INPUT select

“

ISEL”

( D3、D4 ) = ( L、L )：L＋R

( L、L )：L－R

( L、H )：MIC

( H、H )：CLK OFF

D5

D6

OUTPUT select

“

OSEL”

( D5、D6 ) = ( L、L )：FWD (L, R in phase)

( L、L )：REV (R in opposite phase)

( L、H )：MIC MIX

( H、H )：NORMAL

D7

Delay out “DOSW”

H : output ON

L : output OFF

D8

D9

D10

Delay volume

“

DLYVOL”

Delay signal / volume setting

"Refer to the separate table."

D11

D12

D13

Feedback volume

“

FBVOL”

Feedback / volume setting

"Refer to the separate table."

D14

Latch control

(D5, D6) = (L, H) : latch

Others are not latch