LG -P940 Service Manual page 38

3. TECHNICAL BRIEF
ABE Overview
The audio back end (ABE) module is a subsystem that manages various audio and voice uplink and downlink
streams between the initiator (the Cortex™-A9 microprocessor unit [MPU], digital signal processor [DSP], or
direct memory access [DMA] controller) and the peripheral physical interfaces (multichannel buffered serial port
[McBSP], SLIMbus®, digital microcontroller [DMIC], multichannel pulse density modulation [McPDM], and
multichannel audio serial port [McASP]).
The ABE module handles the audio processing for the applications. It receives voice or audio samples from the
initiator or the external audio chip (TWL6040 or other) and sends them to the peripheral interfaces or memories
after processing. The ABE can perform buffering of audio samples, mix audio with a voice down stream and/or a
microphone up stream (sidetone), and can apply some post-processing.
The ABE integrates the following modules:
• Peripheral physical interfaces:
– Three McBSP modules
– One McASP module
– One mobile industry processor interface (MIPI) SLIMbus interface
– One DMIC module to support up to six mono and up to three stereo digital microphones
– One McPDM module to support interconnect with an external audio chip.
• Audio engine (AE):
– Performs real-time signal processing like sample rate conversion, filtering, equalizing, and side-tone
– Audio traffic controller (ATC):
• Performs data move in the ABE
• Generates interrupt requests to the DSP and Cortex-A9 interrupt controllers
– On-chip memory:
• 64KB of RAM; 32-bit data memory (DMEM)
• 6KB for coefficient memory RAM (CMEM)
• 18KB for sample memory RAM (SMEM)
• 8KB for program memory RAM (PMEM)
• Local L4 interconnect (L4_ABE) to:
– L3 interconnect
– Cortex-A9 MPU
– DSP
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