TCA6507_16 Datasheet, PDF (19/45 Pages) Texas Instruments – Low-Voltage 7-Bit I2C and SMBus LED Driver

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TCA6507
SCPS164C – MAY 2007 – REVISED JANUARY 2016
8.5.4 Control Register and Command Byte
Following the successful acknowledgment of the address byte, the bus master sends a command byte, which is
stored in the control register. The last four bits (B0, B1, B2 and B3) of this command byte determine the internal
registers (Select0, Select1, Select2, Fade-ON Time, Fully-ON Time, Fade-OFF Time, First Fully-OFF Time,
Second Fully-OFF Time, Maximum Intensity and Initialization) that are affected. The command byte is sent only
during a write transmission.
After the command byte is received, the I²C master starts sending data bytes. The first data byte goes into the
internal register defined by the command byte. Bit B4 in the command byte is used to determine the
programming mode. If B4 is low, all data bytes are written to the register defined by B0, B1, B2, and B3. If B4 is
high, the last four bits of the command byte are automatically incremented after the byte is written, and the next
data byte is stored in the corresponding register. Registers are written in the sequence shown in Table 6. Once
the Initialization register (register 0x0A) is written to, the command byte returns to 0 (Select0 register).
The upper three bits (B7–B5) of the command byte must be programmed as zeroes for proper operation.
If a STOP condition occurs after the command byte is received, the TCA6507 stores the command byte and then
remains idle until the I²C master sends the next operation.
B7 B6 B5 B4 B3 B2 B1 B0
Figure 18. Control Register Bits
BIT
B7
B6
B5
B4
B3
B2
B1
B0
Table 3. Command Byte
FUNCTION
Reserved. Must be programmed as 0.
Reserved. Must be programmed as 0.
Reserved. Must be programmed as 0.
Auto increment. 1 = Auto increment enabled. 0 = Auto increment disabled.
Register address 3.
Register address 2.
Register address 1.
Register address 0.
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