34825 datasheet(23/39 Pages) FREESCALE

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MIC

VBUS

…...

RN-1

HOLD

Audio_R

Audio_L

D+

D-

GND

AUDIO

ACCESSORY

SEND/END

Analog Integrated Circuit Device Data

Freescale Semiconductor

34825

FUNCTIONAL DEVICE OPERATION

OPERATION AFTER IDENTIFICATION

Figure 16. Audio Accessory with Remote Control and Microphone

20 ms

Key Press

20 ms

TKP

TLKP

INT

LKP

LKR

INT

ADC Time

Interrupt Register read

20 ms

Figure 17. The Remote Control Key Pressing Timing

TEST ACCESSORY

The Test Accessories listed in Table 21 are special USB

cables and UART cables for test and R/D purpose. It has an

ID resistance to differentiate it from a regular USB cable or

UART cable. The test accessory has four ID resistance

values to distinguish the test cable type. The detection result

sets the TEST1 and the TEST2 outputs and turns on or off

the USB switches, UART switches, and the power MOSFET

automatically, as shown in the Table 8.

The TEST1 and the TEST2 outputs are High and Low

respectively by default but can be changed by the TEST1 and

TEST2 bits in the S/W Control 2 register, if the accessory is

NOT a test cable. If the accessory is a test cable, the TEST1

outputs Low always and the TEST2 is dependent on the

actual test cable. The TEST1 and TEST2 output cannot be

changed by the TEST1 and the TEST2 bits in the S/W

Control 2 register. The corresponding analog switches, either

USB or UART switches, are turned on automatically in the

case of a test cable. The TEST1, TEST2, and the switch

status are summarized in Table 8.

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