WT21-A-HCI Ver la hoja de datos (PDF) - Unspecified
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WT21-A-HCI Datasheet PDF : 57 Pages
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Figure 17: Multi-Slot Operation with Two Slots and 8-bit Companded Samples
8.1.5 GCI Interface
WT21 is compatible with the General Circuit Interface (GCI), a standard synchronous 2B+D
ISDN timing interface. The two 64kbps B channels can be accessed when this mode is
configured.
Figure 18: GCI Interface
The start of frame is indicated by the rising edge of PCM_SYNC and runs at 8kHz. With WT21 in
Slave mode, the frequency of PCM_CLK can be up to 4.096MHz.
8.1.6 Slots and Sample Formats
WT21 can receive and transmit on any selection of the first four slots following each sync pulse.
Slot durations can be either 8 or 16 clock cycles. Durations of 8 clock cycles may only be used
with 8-bit sample formats. Durations of 16 clocks may be used with 8-bit, 13-bit or 16-bit
sample formats.
WT21 supports 13-bit linear, 16-bit linear and 8-bit μ-law or A-law sample formats. The sample
rate is 8ksamples/s. The bit order may be little or big endian. When 16-bit slots are used, the 3
or 8 unused bits in each slot may be filled with sign extension, padded with zeros or a
programmable 3-bit audio attenuation compatible with some Motorola CODECs.
Bluegiga Technologies Oy
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