LP3944 Datasheet, PDF (8/12 Pages) National Semiconductor (TI) – RGB/White/Blue 8-LED Fun Light Driver

Application Notes (Continued)
AUTO INCREMENT
Auto increment is a special feature supported by the LP3944
to eliminate repeated chip and register addressing when
data are to be written to or read from registers in sequential
order. The auto increment bit is inside the register address
byte, as shown in Figure 6. Auto increment is enabled when
this bit is programmed to “1” and disabled when it is pro-
grammed to “0”.
FIGURE 6. Register Address Byte
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In the READ mode, when auto increment is enabled, I²C
master could receive any number of bytes from LP3944
without selecting chip address and register address again.
Every time the I²C master reads a register, the LP3944 will
increment the register address and the next data register will
be read. When I²C master reaches the last register (09H
register), the register address will roll over to 00H.
In the WRITE mode, when auto increment is enabled, the
LP3944 will increment the register address every time I²C
master writes to register. When the last register (09H regis-
ter) is reached, the register address will roll over to 02H,
because the first two registers in LP3944 are read-only
registers. It is possible to write to these two registers, and the
LP3944 will acknowledge, but the data will be ignored.
In the LP3944, registers 0x01, 0x08 and 0x09 are not func-
tional. However, it is still necessary to read from 0x01 and to
write to 0x08 and 0x09 in Auto Increment mode. They cannot
be skipped.
If auto increment is disabled, and the I²C master does not
change register address, it will continue to write data into the
same register.
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FIGURE 7. Programming with Auto Increment Disabled (in WRITE Mode)
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FIGURE 8. Programming with Auto Increment Enabled (in WRITE Mode)
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