TSL2563CS datasheet(10/38 Pages) TAOS

10 / 38 page

TSL2562, TSL2563

LOW-VOLTAGE

LIGHT-TO-DIGITAL CONVERTER

TAOS066J − MAY 2007

The LUMENOLOGY r Company

www.taosinc.com

When an SMBus Block Write or Block Read is initiated (see description of COMMAND Register), the byte

following the COMMAND byte is ignored but is a requirement of the SMBus specification. This field contains

the byte count (i.e. the number of bytes to be transferred). The TSL2562 (SMBus) device ignores this field and

extracts this information by counting the actual number of bytes transferred before the Stop condition is

detected.

When an I2C Write or I2C Read (Combined Format) is initiated, the byte count is also ignored but follows the

SMBus protocol specification. Data bytes continue to be transferred from the TSL2563 (I2C) device to Master

until a NACK is sent by the Master.

The data formats supported by the TSL2562 and TSL2563 devices are:

D Master transmitter transmits to slave receiver (SMBus and I2C):

− The transfer direction in this case is not changed.

D Master reads slave immediately after the first byte (SMBus only):

− At the moment of the first acknowledgment (provided by the slave receiver) the master transmitter

becomes a master receiver and the slave receiver becomes a slave transmitter.

D Combined format (SMBus and I2C):

− During a change of direction within a transfer, the master repeats both a START condition and the slave

address but with the R/W bit reversed. In this case, the master receiver terminates the transfer by

generating a NACK on the last byte of the transfer and a STOP condition.

For a complete description of SMBus protocols, please review the SMBus Specification at

http://www.smbus.org/specs. For a complete description of I2C protocols, please review the I2C Specification

at http://www.semiconductors.philips.com.

Data Byte

Slave Address

Acknowledge (this bit position may be 0 for an ACK or 1 for a NACK)

Stop Condition

Read (bit value of 1)

Start Condition

Repeated Start Condition

Write (bit value of 0)

Shown under a field indicates that that field is required to have a value of X

... Continuation of protocol

Master-to-Slave

Slave-to-Master

Figure 7. SMBus and I2C Packet Protocol Element Key

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