12
Troubleshooting
12.1
No LED activity detected on the STEVAL-PCC020V1 interface board
When the board is plugged to the system:
•
LED D2 lights up, indicating the MCU is working, hence, the power supply is present;
•
the yellow LED D1 starts blinking, indicating the USB port has been enumerated correctly.
If the LEDs are not working properly, it might be due to a power supply issue.
Procedure
Step 1.
Locate fuse F1 (close to the USB connector)
Figure 49.
STEVAL-PCC020V1 interface board fuse
Step 2.
Check the voltage between J1 ground (shield) and the right side of the fuse.
If it is not 5 V ±10%, it means an overcurrent occurred and the fuse has blown.
Step 3.
Replace the fuse (0.5 A), after trying to fin out the root cause.
12.2
USB yellow LED shutdown in few seconds
The yellow LED D1 is wired to the USB suspend signal from CP2102; that is, it only lights up when the USB port
is not in USB suspend mode.
Note:
By default (for Windows 7 and 8), the system forces external devices to enter suspend mode to save power (for
example, when the COM port is not used). It does not mean the power supply is shut down, but the CP2102
goes into low power mode.
To avoid this issue, select the SiLabs COM port, and go to the Power Management Tab and uncheck “Allow the
Computer to turn off this device to save power”.
Procedure
Step 1.
go in the
Device Manager
UM2342
Troubleshooting
UM2342
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Rev 1
page 40/57
