AK2305 Datasheet, PDF (14/43 Pages) Asahi Kasei Microsystems – Dual PCM CODEC for ISDN TERMINAL ADAPTER

ASAHI KASEI
[AK2305]
RESET
POWER ON RESET
AK2305 automatically generates the internal reset pulse at the time of power on. Then all circuits are reset
and internal registers are initialized.
After reset operation, CODEC CH0/CH1 circuits start to be initialized. It takes 150ms(typ.), 330ms(max) from
power on to completion of initialization.
*)Output pins remain Hi-Z during the period in which the internal reset pulse is high(See page 5).
The period of the reset pulse is about 20ms(typ), 200ms(max).
POWER-UP TIME FOR POWER ON RESET
When power-up time is no longer than 50ms(=5tau:tau is time constant), Power On Reset works normally.
When the time is longer than 50ms, Power On Reset is not available and no internal registers are initialized.
All registers must be written.
RECOMMENDED START UP PROCEDURE
The following start up procedure is recommended when AK2305 is going to power up.
Power up
Wait 200ms
*In case of VDD rising time
=50ms(=5tau)
- TNOE0,1=” L”
- FSn=” L”
- BCLK=” L”
When 1stFS and BCLK are set to “ L” ,
CODEC ch0,ch1 dose not interface with
external devices.
Write data to the internal
register through serial I/F
- Write data to the internal register
before CODEC starts working.
Supply FSn and BCLK
Wait 130ms
CODEC starts working
- CODEC Initialization starts.
- CODEC Initialization complete.
C0029-E-02
14
1999/8