LG -P940 Service Manual page 44

3. TECHNICAL BRIEF
PDM Interface
The PDM interface is the over-sampled serial interface used for communication between Phoenix audio and the
application processor companion chip.
PDM_CLK is 19.2 MHz or 17.64 MHz and data rate represented by PDM_FRAME is respectively 1.92 MHz or 1.764
MHz. Words of data can be transmitted from OMAP to ABB chip using PDM_DN line (downlink path) but words
of data can also be transmitted from ABB chip to OMAP using PDM_UP line (uplink path).
Both chips are synchronized through PDM_FRAME line. By default OMAP is the owner of PDM_FRAME but
during transmission, ABB chip can send back to OMAP some low-latency data by using frame line. This will be
detailed later in this chapter.
Phoenix audio PDM interface consists of three different modes, Normal mode, Command mode and Test mode.
Normal mode and Command mode are intended to use with OMAP McPDM. Test mode is designed for
evaluation and production test.
Fig.3.7.6.2 PDM Interface connectivity between Phoenix and OMAP4 McPDM
Fig.3.7.6.2 PDM Interface connectivity between Phoenix and OMAP4 McPDM
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