AN2148 - APPLICATION NOTE

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In audio mode it is necessary to tie the OE_TP_INT/ pin to a high level to deactivate the USB driver.

When all the pull-up and pull-down resistors are disconnected, the D+ and D- USB lines will be in high

impedance state and it is possible to send audio signals over the lines. To be able to detect carkit

interrupts, it is necessary to set the audio_en bit of the Control Register 3. Then, depending on the

protocol used (either four-wire or five-wire) it is necessary to set the proper bits of the Interrupt Mask

False and Interrupt Mask True registers. If a four-wire protocol is used then D+ carkit interrupt should be

utilized and therefore the cr_int bit of interrupt mask registers should be set. If a five-wire protocol is used

then ID line carkit interrupt can be utilized and therefore the id_gnd bit of interrupt registers should be set.