Functional description
FRDM-K32L3A6 Freedom Development Board, User’s Guide, Rev. B0, 09/2019
8
NXP Semiconductors
These jumpers provide access to insert ammeters in all the supplies connecting to the K32L3A6 device.
They also provide a means of connecting external supplies to any of the K32L power pins.
In the case of using a single supply, an ammeter can be placed across J18 to measure the entire system
current. Alternatively, an ammeter can be placed across J53 pins 2 and 3 to measure current with the
LEDs and sensor core taken out of the reading. To minimize the current drawn by the other board
components and measure the current drawn by just the K32L3A6 device, the following steps are
recommended
Cut the trace under J5 to isolate the power indicator LED (if using J18)
Cut the trace under J47 to isolate the photo transistor
Place the SPI flash in ultra-low power mode by writing the command value 0xB9.
3.3 Universal Serial Bus (USB)
The K32L3A6 MCU features a full-speed USB module with device capability and built-in transceiver.
The FRDM-K32L3A6 board routes the USB D+ and D- signals from the K32L3A6 MCU directly to the
onboard micro USB connector (J8) via the required 33 ohm resistors.
Figure 6
shows the complete USB
circuit.
Figure 6. USB connector circuit
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