Hardware
2.4.5
Super Cap
A 100-mF (0.1-F) super cap is mounted onboard and allows powering the system without any external
power. This highlights the ultra-low power of the MSP430FR5969 target device. See how long you can run
your application on the super cap alone!
2.4.5.1
Charging the Super Cap
To charge the super cap, jumper J11 is used. By default there is no jumper across J11. Place a jumper
across J11 to charge the super cap. If another jumper is not handy, the GND jumper on the isolation
jumper block can be used- as this jumper doesn't actually disconnect the GND connection.
To charge the super cap, power must be coming from a debugger (eZ-FET or JTAG) or external power
through J10. External power through J1 or a BoosterPack will not charge the super cap through J11.
Placing a jumper across J11 will charge the super cap when there is 3.3-V V
cc
present, regardless of the
state of the Bypass/Use J2 jumper, however if J2 is in the "Bypass" state, changing it over to the "Use"
state will remove power from the target MSP430FR5969 and it will be reset.
2.4.5.2
Using the Super Cap
To use the super cap to power the LaunchPad, first change the J2 jumper to select "Use" and then set a
jumper on J11 to charge the super cap. After waiting for it to charge, any external power can be removed
from the system, and it will be powered completely by the super cap.
To remove any additional power drain from the super cap, remove any jumper to disconnect power to any
external source. This can be J11, J10, or J13 depending on the power configuration. This prevents the
super cap from back-powering the debug circuitry or any external power circuitry connected.
The most effective method for charging the capacitor is outlined in the following steps. These steps
assume the LaunchPad is powered by USB cable through the eZ-FET debugger.
1. Set "Power Selector" jumper (J10) to "Debugger" position.
2. Set jumper J2 to "Use" super cap position.
3. Set jumper J11 to "Charge" super cap position.
4. Set "V+" jumper J13.
5. Connect board to PC with USB cable.
6. Allow two to three minutes for the super cap to charge (time may vary depending on initial charge of
the super cap) to full V
CC
.
7. Remove the "V+" jumper J13.
For power configuration diagram, see
19
SLAU535B – February 2014 – Revised July 2015
MSP430FR5969 LaunchPad™ Development Kit (MSP
‑
EXP430FR5969)
Copyright © 2014–2015, Texas Instruments Incorporated
