TCA7408EVM Datasheet, PDF (3/14 Pages) Texas Instruments – Works with MSP430 Launchpad

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Setup
1.6.2 Power Supply (*Optional)
To ensure correct functionality of the LEDs a 5V supply at 300mA is recommended (refer to note in
section 2.3.1). If not using a USB cable to power the LaunchPad a 3.3V power supply at 200mA is
required.
2 Setup
This section describes the jumpers and connectors on the EVM.
2.1 Connectors and Jumpers
2.1.1 J1 & J2 – LaunchPad Headers
These connectors mate with the male headers on the LaunchPad.
2.1.2 J3 – External LED Power
This connector is where the external +5V supply is attached to power the two RGB LEDs.
2.1.3 J4 – TCA7408 GPIO
This is a pin out of the four unused GPIO pins from the TCA7408, GPIO4-GPIO7.
2.1.4 J5 – Feedback loop
For the TPL0401A to function as a voltage reference circuit the negative feedback loop must be shorted,
placing a jumper across this header will short the inverting input to the output.
2.1.5 J6 – LED or Op-amp
This header controls what the TPL0401B is attached to. When shorted across position 1 and 2 the
TPL0401B is connected in series with the external resistor to control the current through the LED driver.
When shorted across position 2 and 3 the TPL0401B is connected to the inverting input of the op-amp to
change the gain of the circuit.
2.1.6 J7 – Op-amp input
This header controls the input to the non-inverting pin of the LMV321. When shorted across position 1 and
2, the TPL0401A in a voltage divider mode is attached to the non-inverting input of the LVM321. This
setup is used to test the voltage reference setup. When shorted across pins 2 and 3, the SMA connector
is attached to the non-inverting input.
2.1.7 J9 – Test Points
This connector offers test points for the serial data lines, SDA, SCL and the DIN that drives the TCA5405.
Table 1. Description of Connectors and Jumpers
Label Description
J1, J2 Connectors to interface with LaunchPad
J3 External 5V for LED
J4 GPIO4-GPIO7 from TCA7408
J5 Control jumper to short feedback loop
J6 Jumper to control LED or Op-Amp
J7 Jumper to control input to Op-Amp
J8 SMA/B Footprint for external input
J9 Test points for DIN, SDA and SCL
SCPU034 – December 2011
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