Texas Instruments TCA8418E, User Manual

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Setup
Table 2. Default TCA8418E Register Values When Using the LaunchPad (continued)
Register Register Name Default Value for EVM Comment
0x2C GPIO_PULL1 0x00
0x2D GPIO_PULL2 0x00
0x2E GPIO_PULL3 0x00
5.5 Getting Started Using the TCA8418E-EVM
5.5.1 Evaluating the TCA8418E EVM without the LaunchPad
1. To power the TCA8418E-EVM without the LaunchPad, apply a 3.3-V, 100-mA power supply to TP1
(VCC pin). Although 3.3 V is preferred, the voltage range can be from 1.65 V to 3.6 V.
2. Attach an external microcontroller to J3 to provide SCL and SDA inputs for I
2
C. Keep in mind that SCL
and SDA are pulled up to VCC on the TCA8418E-EVM through 4.7-k Ω resistors. Therefore, using the
same power supply for the microcontroller and the TCA8418E-EVM is recommended.
3. Use the built-in 3x3 keypad on the TCA8418E-EVM or use J5 to attach an external keypad. If attaching
an external keypad, the KP_GPIO registers (0x1D, 0x1E, and 0x1F) should be configured to
accommodate the additional keys.
5.5.2 Evaluating the TCA8418E EVM with the LaunchPad
After completing the steps in Section 5.2 , launch the TCA8418E-EVM software. The screen will look like
Figure 13 .
Figure 13. TCA8418E-EVM GUI After Connecting the LaunchPad to the Computer
11 SLVUAA2 – August 2014 TCA8418E Keypad Scan EVM
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