LC89091JA Datasheet, PDF (18/30 Pages) ON Semiconductor – Digital Audio Interface Receiver

LC89091JA
8.9 Multi Purpose Input/Output (MPIO)
 MPIO can be selected the following input/output by the MPSEL register.
 MPIO needs a pull-up resistor when set to the output.
 When not using MPIO, it uses no connecting (open state).
However, don't choose MPIO by DINSEL or THRSEL register.
8.9.1 Pre-emphasis Flag Output ("MPSEL=0")
 The initial mode outputs pre-emphasis of the channel status that indicates whether there is 50/15s emphasis
parameter for consumer.
 MPIO becomes a Hi-Z output when an emphasis signal is not detected. For this reason, it connects with a pull-up
resistor. The example of use is shown below
MPIO output
Hi-Z (H**)
L
Table 8.9: Pre-emphasis Flag Output
MPIO output conditions
No pre-emphasis
50/15s pre-emphasis
**: When MPIO connects with a pull-up resistor
LC89091JA
DAC
De - emphasis
MPIO
Figure 8.11: MPIO Output Example of Use (Pre-emphasis Output)
8.9.1 S/PDIF data Input ("MPSEL=1")
 MPIO can be used as S/PDIF input terminal by "MPSEL=1".
 MPIO immediately after power-on is set as an output state. For this reason, before input all the S/PDIF signals, MPIO
is set as an input state by MPSEL register. If S/PDIF signal input (RXIN input) before MPSEL register setup and pre-
emphasis flag is detected, MPIO output will short-circuit with peripheral circuitry. Therefore, before S/PDIF signal
input, MPIO setup must be complete.
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