FUSB251

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10

I2C Interface

The FUSB251 includes a full I2C slave controller. The

I2C slave fully complies with the I2C specification version

6 requirements. This block is designed for fast

are shown in below figures respectively.

SWR A

A

A

A

A

A

NOTE: Single Byte read is initiated by Master with P immediately following first data byte

8 bits

8 bits

8 bits

Write Data K+2

Slave Address

Register Address K

Write Data

Write Data K+1

Write Data K+N-1

P

S

WR A

A S

RD A

A

A

NA P

Register address to Read specified

8 bits

NOTE: If Register is not specified Master will begin read from current register. In this case only sequence showing in

Red bracket is needed.

Single or multi byte read executed from current register location

(Single Byte read is initiated by Master with NA immediately following first data byte)

Read Data K+1

Read Data K+N-1

8 bits

8 bits

8 bits

Slave Address

Register Address K

Read Data K

Slave Address

From Master to Slave

S Start Condition

NA NOT Acknowledge (SDA High) RD Read = 1

From Slave to Master

A Acknowledge (SDA Low)

WR Write = 0

P

Stop Condition

SLAVE ADDRESS

Part Number

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

FUSB251UCX

0

1

0

1

0

0

0

R(1)/W(0)

Moisture Detection

CC Moisture Detection

Moisture detection is default disabled. Once CC moisture

detection is enabled, voltage of both CC1_H and CC2_H are

monitored to see if both CCs rise above 170 mV. If they rise

above the voltage, moisture detection started on one of the

CC first, and moisture detection on the other CC is occurred

at the next both CC rising. If only one of CCs rises up above

the threshold, in case of source device attach, CC moisture

detection does not start.

If both CCs cross the threshold, both CC switches are open

momentarily, and FUSB251 supplies 1volt source onto one

of CCs with 320 k

W pull up. And ADC detection is enabled

to measure the voltage of the CC channel. Since moisture in

connector can make leakage path between the CC pin and

other pins including GND, there will be resistance between

CC and GND and it can be detected by ADC. Once moisture

detection is finished on one CC, the other CC channel is also

tried at the next both CC rise. If there is no both CC rise on

either CC within 120 ms from the last detection, it will go to

timer expire. If source or sink device is attached, the timer

will expire. Timer expire is interrupted to host and CC

moisture detection stops and moisture detection is continued

on SBU float voltage detection instead. To be determined as

moisture presence, both CC channels have to be tried and

moisture has to be detected on either of channel with no

timer expire. If moisture is detected, the result is updated in

the register and interrupt is triggered to processor.

Regardless of moisture presence on CC, once detection is

finished, both CC switches are closed again for Type−C

controller to use the CC channel. Moisture detection range

can be changed by I2C register, Threshold1 in 0x08. Once

the measured resistance is less than the threshold, it will be

detected as moisture.

If sink device is attached while host with FUSB251 is on

DRP toggle, both CC will rise together, So, CC moisture

detection will happen. And, FUSB251 can find the Rd in

sink device because the Rd, 5.1 k

W, is in moisture detection

range. But the other CC channel detection will end up as

timer expire because there will be no both CC rise after

attach. So, the final result will be timer expire and moisture

detection will continue on SBU pins.

To support audio and debug accessories which have two

terminations on both CC, there is a register bit in the control

register, bit7 in 0x02. The register bit makes moisture

detection occur on every other both CC rising so moisture

detection skips for Type−C detection can happen during the

time.