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SLYU047A – April 2018 – Revised May 2018
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Copyright © 2018, Texas Instruments Incorporated
DRV5055EVM
3.3.10
U17, R28-R34, R40-R42, D13-D16
U17 is the TCA9535 GPIO extender. The MSP430FR4133 and TCA9535 communicate through the I
2
C
protocol, which requires pullup resistors R32 and R33. The TCA9535 is the slave device, whereas the
MSP430FR4133 is the master device.
U16 communicates the K1 state on pins P00, P01, and P02 to the MSP430FR4133.
Pins P03-P07 and P10-P16 are defined as outputs for toggling LEDs D5-D16 according to commands
from the MSP430FR4133.
Resistors R28-R31 are 10-k
Ω
resistors meant to limit current through LEDs D13-D16 when a
corresponding TCA9535 output pin is toggled low.
Resistors R40-R43 are for power saving when any the corresponding TCA9535 output pin is high.
By default, TCA9535 GPIOs are all disabled and thus to enable these GPIOs the 10-k
Ω
, R34, ties pin 1 to
3.3-V VCC.
3.3.11
U19
U19 is the VI-401-DP-RC-S LCD that displays the measurements of a selected device for a given selected
measurement format.
3.3.12
M1, C49-C42
M1 is the MSP430FR4133 that samples the analog output from the DRV5055 and converts those outputs
into a bit pattern that conveys the correct output measurement on the LCD display. M1 uses capacitors
C49-C42 to convert the input voltage to a boosted square wave output signal capable of driving the LCD
display. M1 also gathers information from push-button S1, U17, the signal fed through U20, and signals
from U5-U12. M1 also commands U17 to turn on the LEDs of interest.
3.3.13
U21
U21 is a switch that serves as a GPIO extender to provide on additional pin with a voltage signal suitable
for the LCD.