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Using the Evaluation Software
6 Using the Evaluation Software
6.1 Register Interface (Direct Write and Read)
A register control established through an I
2
C compatible serial interface allows the user to directly program
the registers by writing to and reading from the memory map registers. This provides the user with added
flexibility in controlling the different functions of the LP3907. However, we caution the user to use this
function only for debugging purposes, because sending wrong values could damage the part. Sliders and
buttons provided below will accomplish the same commands in a more interactive way, and is also less
prone to mistakes.
6.1.1 Using the Register Controls
Direct Register Access (left section of Figure 5) is divided into two parts: Direct Register Write on the left
and Direct Register Read on the right. To write to a specific register, simply type the register address in
hexadecimal into the box, set the value through the specific bit buttons, and click “Write”. To read a value
in binary, type in the register address in hexadecimal into the box on the right and click “Read”.
For example, to turn off all regulators except the LDO1 regulator, this could be done by typing in the
number 10 into the “Addr (HEX):” box, clicking binary placeholder number 4, and then clicking store. The
register should reflect the stored value assigned (00010000) when the user clicks the button Read.”
Please note that the same function could be more easily implemented through the graphical interfaces,
and is in the users’ best interest use Direct Register Access only when necessary.
The register profile interface allows the user to save all his/her settings for use at a later time. The GUI is
programmed to accommodate saving two sets of profiles.
Figure 5. Register Interface
6.2 Chip Control Interface
If the IC changes state and/or if the user assigns a new value to a register, the GUI may not reflect those
changes if the “Auto Poll” button is not enabled. By hitting the “Read All” button, the user will manually
renew the GUI so that it reflects the most current state of the IC.
The “Auto Poll” check box refreshes the GUI every second to ensure that it mirrors the current state of the
chip. The checkbox is on by default so that the user can constantly monitor the status of the IC. Similarly,
the “Auto Write” check box will enable the signals generated from using the sliders or buttons to be sent to
the chip. The check box is on by default, and should be unchecked if the user wishes not to change the
settings on the chip.
The “Defaults” button will set all registers on the chip to the default settings when clicked. The “Measure”
button will update the values measured on the chip by ADCs on the USB interface.
The Quit button allows the user to exit the program.
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SNVA233ASeptember 2007Revised April 2013 AN-1619 Evaluation Kit for LP3907 — Programmable Power Management
Unit with 1
2
C Compatible Interface
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