[AK4685]
OPERATION OVERVIEW
■ System Clock
The AK4685 has three audio serial interfaces (PORTA, PORTB and PORTC) which can be operated asynchronously.
The PORTA and PORTC are the audio data interfaces for DAC1 and DAC2, the PORTB is for ADC. At each PORT, the
external clocks, which are required to operate the AK4685 in slave mode, are MCLKA, MCB, LRCKA/B/C, and
BICKFA/B/C. The MCLKA/C and MCB must be synchronized with LRCKA/B/C but the phase is not critical.
■ Master/Slave Mode
The MSB pin selects master/slave mode of PORTB. PORTA and PORTC are slave mode only. In master mode, LRCKB
pin and BICKB pin are output pins. In slave mode, LRCKA/B/C pins and BICKA/B/C pins are input pins (Table 1).
The PORTB is in slave mode at power-down (PDN pin = “L”). To change it to master mode, set the MSB pin to “H”.
Until setting the MSB pin to “H”, LRCKB and BICKB pins are input pins. Around a 100kohm Pull-up (or down) resistor
is required to prevent floating of these input pins.
PORTB (ADC)
BICKB, LRCKB
PORTA/C (DAC1/2)
BICKA/C, LRCKA/C
PDN pin
MSB pin
L
H
L
Input (slave mode)
Output “L”(master mode)
Input (slave mode)
Input (slave mode)
Input (slave mode)
Input (slave mode)
Input (slave mode)
L
H
H
Output (master mode)
Table 1. Master/Salve Mode
MS1106-E-00
2009/08
- 17 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
