LP3944ISQEV National Semiconductor, LP3944ISQEV Datasheet - Page 8

• Manufacturer Part Number: LP3944ISQEV
• Description: BOARD EVALUATION LP3944ISQ
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LP3944ISQEV

• Current - Output / Channel: 25mA
• Outputs And Type: 8, Non-Isolated
• Features: Dimmable, I²C Interface
• Voltage - Input: 2.3 ~ 5.5 V
• Utilized Ic / Part: LP3944
• Core Chip: LP3944
• No. Of Outputs: 8
• Output Current: 25mA
• Dimming Control Type: I2C
• Kit Contents: Board, User Guide
• Development Tool Type: Hardware - Eval/Demo Board
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Voltage - Output: -

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Application Notes
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
In the READ mode, when auto increment is enabled, I
master could receive any number of bytes from LP3944
without selecting chip address and register address again.
Every time the I
increment the register address and the next data register will
be read. When I
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 I
master writes to register. When the last register (09H regis-
ter) is reached, the register address will roll over to 02H,
2
C master reads a register, the LP3944 will
2
C master reaches the last register (09H
FIGURE 7. Programming with Auto Increment Disabled (in WRITE Mode)
FIGURE 8. Programming with Auto Increment Enabled (in WRITE Mode)
(Continued)
FIGURE 6. Register Address Byte
2
2
C
C
8
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”.
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 I
change register address, it will continue to write data into the
same register.
20085311
20085313
20085312
2
C master does not