2.2 - Power and Status LED [U6 Datasheet]

There is a yellow “Power” LED to indicate power, and a green “Status” LED controlled by the main processor.

The Power LED is connected to VS (with a series resistor). It indicates that some voltage is present on VS, but does not indicate whether the voltage is valid or not.

The Status LED flashes on reset and USB enumeration, then remains solid on with flashes to indicate communication (USB) traffic.

Normal Power-Up Status LED Behavior: When the USB cable is connected to the U6, the Status LED should blink a few times and then remain solid on.

LED blinking continuously at about 4 Hz, even with no software running: This indicates that the U6 is in flash mode. See Section 1.2 and reprogram the device.