34825 datasheet(25/39 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

34825

FUNCTIONAL DEVICE OPERATION

LOGIC CONTROL FEATURES

reset caused by the VDDIO input or by the I2C bus lines

belongs to system resets.

The hardware reset condition using the I2C signals is

shown in Figure 20. When both the I2C_SCL and the

I2C_SDA have a negative pulse with time of tRSTI2C, a

hardware reset is generated. The result of the reset is same

as a Power-On-Reset.

The operating waveforms of the hardware reset using the

VDDIO pin are shown in Figure 21. The VDDIO detection has

a deglitch-time tVDDIODGT_F. A glitch on the VDDIO with

duration less than the deglitch time will be ignored. If the

pulse on the VDDIO lasts longer than the deglitch time, a

reset from the VDDIO is detected to generate a reset signal.

To effectively reset the 34825, the reset pulse from the

VDDIO needs be longer than the 150

μs minimum reset

pulse width given in the Dynamic Electrical Characteristics

table.

SOFTWARE RESET

In addition to the two hardware reset types, the system

reset has another reset source, the software reset by writing

‘1’ to the RESET bit in the Control register. The Reset bit will

be cleared to ‘0’ at once since it is of W/C type. The

consequence of the software reset is the same as the

hardware reset. All registers will be reset.

Figure 19. Sources of Reset in 34825

Figure 20. Hardware Reset Using the I2C Bus

Figure 21. Hardware Reset Using the VDDIO Input

INTERRUPT

There are eight interrupt sources in the 34825 causing an

interrupt at the INT pin to the host IC. They are accessory

attachment, accessory detachment, short-key press, long

key press, long-pressed key release, VBUS voltage OVP, the

IC temperature OTP, and either the OVP or the OTP

condition is removed. The 34825 detects each event and sets

reset

VVDDPOR

VDD

2C_SDA

2C-Bus

Reset

Detection

Delay

Time

2C_SCL

VDDIO

Reset

Detection

I2C_SDA

I2C_SCL

Reset

Condition

Start

Condition

Stop

Condition

Reset

8.8~13.5ms

VDDIO

Reset

tVDDIODGT_F

34825 Datasheet(PDF) 25 Page - Freescale Semiconductor, Inc

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