Datasheet

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15
SLAU595A–October 2014–Revised July 2015
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MSP430FR4133 LaunchPad™ Development Kit (MSP ‑ EXP430FR4133)
2.4 Measure MSP430 Current Draw
To measure the current draw of the MSP430FR4133 using a multi-meter, use the 3V3 jumper on the
jumper isolation block. The current measured includes the target device and any current drawn through
the BoosterPack headers.
To measure ultra-low power, follow these steps:
1. Remove the 3V3 jumper in the isolation block, and attach an ammeter across this jumper.
2. Consider the effect that the backchannel UART and any circuitry attached to the MSP430FR4133 may
have on current draw. Consider disconnecting these at the isolation jumper block, or at least consider
their current sinking and sourcing capability in the final measurement.
3. Make sure there are no floating input/output (I/Os). These cause unnecessary extra current draw.
Every I/O should either be driven out or, if it is an input, should be pulled or driven to a high or low
level.
4. Begin target execution.
5. Measure the current. Keep in mind that if the current levels are fluctuating, it may be difficult to get a
stable measurement. It is easier to measure quiescent states.
Alternatively, EnergyTrace technology can be used to measure the same current, and see energy profiles
through integrated GUI in CCS and IAR. EnergyTrace allows you to compare various current profiles and
better optimize your energy performance!
2.5 Clocking
The MSP-EXP430FR4133 provides an external clock in addition to the internal clocks in the device.
• Y1: a 32-kHz crystal
The 32-kHz crystal allows for lower LPM3 sleep currents than do the other low-frequency clock sources.
Therefore, the presence of the crystal allows the full range of low-power modes to be used.
The internal clocks in the device default to the following configuration:
• MCLK: DCO, 2 MHz
• SMCLK: DCO, 2 MHz
• ACLK: REFO, 32.768 kHz
For more information about configuring internal clocks and using the external oscillators, see the
MSP430FR4xx and MSP430FR2xx Family User's Guide (SLAU445).
2.6 Using the eZ-FET Emulator With a Different Target
The eZ-FET emulator on the LaunchPad can interface to most MSP430 derivative devices, not just the on-
board MSP430FR4133 target device.
To do this, disconnect every jumper in the isolation jumper block. This is necessary, because the emulator
cannot connect to more than one target at a time over the Spy-Bi-Wire (SBW) connection.
Next, make sure the target board has proper connections for SBW. Note that to be compatible with SBW,
the capacitor on RST/SBWTDIO cannot be greater than 2.2 nF. The documentation for designing MSP430
JTAG interface circuitry is the MSP430 Hardware Tools User's Guide (SLAU278).
Finally, wire together these signals from the emulator side of the isolation jumper block to the target
hardware:
• 5 V (if 5 V is needed)
• 3.3 V
• GND
• SBWTDIO
• SBWTCK
• TXD (if the UART backchannel is used)
• RXD (if the UART backchannel is used)
• CTS (if hardware flow control is used)
• RTS (if hardware flow control is used)
This wiring can be done either with jumper wires or by designing the board with a connector that plugs
into the isolation jumper block.