Datasheet

25 SERDESUB-21USB User’s Guide SNLU101 – April 2012

Procedure – Camera Mode:

1) Connect the 1.8V and 3.3V power with +1.8V and +3.3V supplies accordingly. Keep

the power off.

2) Verify that all the jumper positions and switches are correctly set.

NOTE: For Camera Mode, the default settings for switch S1-M_S on S1 for the

DS90UB903Q Serializer and DS90UB904Q Deserializer boards must be reversed.

DS90UB903Q board: S1 DS90UB904Q board: S1

3) Connect the USB interface cable between P2 (DS90UB903Q board) connector and

J2 connector (DS90UB904Q board). Note that hot-plugging assertion of cable

between Serializer and Deserializer is not supported.

4) Set hardware configuration for DS90UB903Q Serializer and DS90UB904Q

Deserializer devices

a. Verify peripheral device (camera) address is set to 0xA0

b. Set to Camera mode: Serializer MODE (M_S) pin = L and Deserializer

MODE (M_S) pin = H

c. Set Serializer and Deserializer I

C slave address on ID[x] (CAD) pin:

iii. Serializer Rid=0ohm; Serializer I

C slave address is 0xB0

iv. Deserializer Rid=0ohm; Deserializer I

C slave address is 0xC0

5) Turn on the +1.8V and +3.3V power supplies

6) The DS90UB904Q Deserializer I

C slave is enabled to receive data directly from

the I

C Master Controller. I

C transfers are processed in a one byte basis. After

receiving one byte, the Deserializer slave will need to acknowledge (ACK) the

transfer to receive the next following byte. The Deserializer slave holds SCL low

(clock stretch) for the required period until an ACK (or NACK) is established and

then releases it. The Deserializer I

C slave acknowledges all the transfers

addressed to Deserializer, Serializer, or remote device.

7) Before initiating any I

C commands, the Deserializer needs to be programmed with

the target slave device addresses and Serializer device address. SER_DEV_ID

SLAVE_x_INDEX registers 0x08h~0x17h set the remote target slave addresses. In