TSL2568, TSL2569
LIGHT-TO-DIGITAL CONVERTER
TAOS091D DECEMBER 2008
12
r
r
Copyright E 2008, TAOS Inc.
The LUMENOLOGY r Company
www.taosinc.com
Command Register
The command register specifies the address of the target register for subsequent read and write operations.
The Send Byte protocol is used to configure the COMMAND register. The command register contains eight bits
as described in Table 3. The command register defaults to 00h at power on.
Table 3. Command Register
6
7
5
4
ADDRESS
2
3
1
0
0
0
0
0
0
0
0
0
Reset Value:
COMMAND
CLEAR
CMD
WORD
BLOCK
FIELD
BIT
DESCRIPTION
CMD
7
Select command register. Must write as 1.
CLEAR
6
Interrupt clear. Clears any pending interrupt. This bit is a write-one-to-clear bit. It is self clearing.
WORD
5
SMB Write/Read Word Protocol. 1 indicates that this SMB transaction is using either the SMB Write Word or
Read Word protocol.
BLOCK
4
Block Write/Read Protocol. 1 indicates that this transaction is using either the Block Write or the Block Read
protocol. See Note below.
ADDRESS
3:0
Register Address. This field selects the specific control or status register for following write and read
commands according to Table 2.
NOTE:  An I
2
C block transaction will continue until the Master sends a stop condition. See Figure 14 and Figure 15. Unlike the I
2
C protocol, the
SMBus read/write protocol requires a Byte Count. All four ADC Channel Data Registers (Ch through Fh) can be read simultaneously in
a single SMBus transaction. This is the only 32-bit data block supported by the TSL2568 SMBus protocol. The BLOCK bit must be set
to 1, and a read condition should be initiated with a COMMAND CODE of 9Bh. By using a COMMAND CODE of 9Bh during an SMBus
Block Read Protocol, the TSL2568 device will automatically insert the appropriate Byte Count (Byte Count = 4) as illustrated in Figure 15.
A write condition should not be used in conjunction with the Bh register.
Control Register (0h)
The CONTROL register contains two bits and is primarily used to power the TSL256x device up and down as
shown in Table 4.
Table 4. Control Register
6
7
5
4
POWER
2
3
1
0
0
0
0
0
0
0
0
0
Reset Value:
CONTROL
Resv
Resv
Resv
Resv
Resv
Resv
0h
FIELD
BIT
DESCRIPTION
Resv
7:2
Reserved. Write as 0.
POWER
1:0
Power up/power down. By writing a 03h to this register, the device is powered up. By writing a 00h to this
register, the device is powered down.
NOTE: If a value of 03h is written, the value returned during a read cycle will be 03h. This feature can be
used to verify that the device is communicating properly.