WT21 View Datasheet(PDF) - Unspecified
Part Name
Description
MFG CO.
'WT21' PDF : 54 Pages View PDF
8
Audio Interfaces
8.1
PCM Interface
The audio Pulse Code Modulation(PCM) interface supports continuous transmission and
reception of PCM encoded audio data over Bluetooth.
Pulse Code Modulation (PCM) is a standard method used to digitise audio (particularly voice) for
transmission over digital communication channels. Through its PCM interface, WT21 has
hardware support for continual transmission and reception of PCM data, thus reducing processor
overhead for wireless headset applications. BlueCore6-ROM (QFN) offers a bi-directional digital
audio interface that routes directly into the baseband layer of the on-chip firmware. It does not
pass through the HCI protocol layer.
Hardware on WT21 allows the data to be sent to and received from a SCO connection.
Up to three SCO connections can be supported by the PCM interface at any one time.
WT21 can operate as the PCM interface master generating an output clock of 128, 256, 512,
1536 or 2400kHz. When configured as a PCM interface slave, it can operate with an input clock
up to 2400kHz. WT21 is compatible with a variety of clock formats, including Long Frame Sync,
Short Frame Sync and GCI timing environments.
It supports 13-bit or 16-bit linear, 8-bit μ-law or A-law companded sample formats at
8ksamples/s and can receive and transmit on any selection of three of the first four slots
following PCM_SYNC. The PCM configuration options are enabled by setting the
PSKEY_PCM_CONFIG32 (0x1b3).
WT21 interfaces directly to PCM audio devices including the following:
8.1.1 PCM Interface Master/Slave
When configured as the master of the PCM interface, BlueCore6-ROM (QFN) generates PCM_CLK
and PCM_SYNC.
Bluegiga Technologies Oy
Page 27 of 56
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