User`s guide

4-32 Intel
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StrongARM
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SA-1110 Microprocessor Development Board User’s Guide
Hardware Considerations
UDA1341 Line1 input right channel analog input mixer as well as to the 2.5 mm headset jack. This
allows the UCB1300 to directly drive the phone headset as well as an additional input to the audio
mixing functions in the UDA1341 and SA-1110.
4.12.7 Audio System Routing and Mixing Diagram
Figure 5-5 provides a guide to managing the audio routing and mixing. The UDA1341 allows
mixing of the Line 1 and Line 2 inputs. The mix is specified by two scaling factors (shown as M in
Figure 5-5) that are applied to the Line 1 and Line 2 stereo inputs before they are added together.
When used for system routing and mixing, the left and right stereo channels are used to manage
mono sources such as radio and telephony sound. All UDA1341 control is through the L3 interface
that is driven by SA-1110 GPIO bits.
The system is designed to work in two modes:
• UDA1341 loopback
• UDA1341 digital routing with mixing in the SA-1110 device
4.12.7.1 UDA1341 Loopback Mode
First is the basic mode that uses the UDA1341 in loopback mode as a system audio router and
mixer. Audio_On, which is bit 8 in the BCR, enables the UDA1341 digital loopback that is
implemented in the CPLD glue logic. This loopback mode allows the mixing and selecting of the
following sources and destinations:
• The main microphone is selected or mixed with the UCB1300 speaker to feed the radio
microphone and UCB1300 microphone.
• The UCB speaker is selected or mixed with the radio speaker out to feed the mini speaker or
headphone/headset.
4.12.7.2 UDA1341 Digital Routing with Mixing in the SA-1110
In this mode, the mixing circuits in the UDA1341 are still available, however, the SA-1110 SPI
port is active and all digital data is routed through the SA-1110 device and back out to the
UDA1341. This allows the OS to mix any combination of sources and route the result to the system
speaker or headphones or radio microphone.