w681310 Winbond Electronics Corp America, w681310 Datasheet - Page 12

• Manufacturer Part Number: w681310
• Description: 3v Single-channel Voiceband Codec
• Manufacturer: Winbond Electronics Corp America

The IDL interface mode is selected when the BCLKR pin is connected to V
sync cycles. It can be used as a 2B+D timing interface in an ISDN application. The IDL interface
consists of 4 pins : IDL SYNC (FST), IDL CLK (BCLKT), IDL TX (PCMT) & IDL RX (PCMR). The FSR
pin selects channel B1 or B2 for transmit and receive. The data for channel B1 is transmitted on the first
positive edge of the IDL CLK after the IDL SYNC pulse. The IDL SYNC pulse is one IDL CLK cycle
long. The data for channel B2 is transmitted on the eleventh positive edge of the IDL CLK after the IDL
SYNC pulse. The data for channel B1 is received on the first negative edge of the IDL CLK after the IDL
SYNC pulse. The data for channel B2 is received on the eleventh negative edge of the IDL CLK after
the IDL SYNC pulse. The transmit signal pin IDL TX becomes high impedance when not used for data
transmission and also in the time slot of the unused channel. For more timing information, see the
timing section.
The system can work at 256 kHz, 512 kHz, 1536 kHz, 1544 kHz, 2048 kHz, 2560 kHz, 4096 kHz &
4800 kHz master clock rates. The system clock is supplied through the master clock input MCLK and
can be derived from the bit-clock if desired. An internal pre-scaler is used to generate a fixed 256 kHz
and 8 kHz sample clock for the internal CODEC. The pre-scaler measures the master clock frequency
versus the Frame Sync frequency and sets the division ratio accordingly. If the Frame Sync is LOW for
the entire frame sync period while the MCLK and BCLK pin clock signals are still present, the W681310
will enter the low power standby mode. Another way to power down is to set the PUI pin to LOW. When
the system needs to be powered up again, the PUI pin needs to be set to HIGH and the Frame Sync
pulse needs to be present. It will take two Frame Sync cycles before the pin PCMT will become low
impedance.
7.4.4. Interchip Digital Link (IDL)
7.4.5. System Timing
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for two or more frame
W681310