I am a little confused. I am looking at the dsPIC33E USB Starter Kit and PIC24EP512GU810-I/PFPIC24EP512GU810-I/PF USB Starter Kit User’s Guide, specifically figure A-7 (page 24) (Starter Kit Interface), and figure A-4 (page 22) (Power Distribution/Switching).
Also reading the section on power supply for the starter kit
2.2.2 Power Supply
There are two ways to supply power to the dsPIC33E or PIC24EP512GU810-I/PFPIC24EP512GU810-I/PF USB Starter Kit:
• Connect the USB Debug connector J2 to a PC running MPLAB using the supplied
mini-B to full-sized A cable
• An external application board with a regulated DC power supply that provides +5V
can be connected to the application board connector (J3) that is provided on the
bottom side of the board
One green LED (D4) is provided to show that the dsPIC33E or PIC24EP512GU810-I/PFPIC24EP512GU810-I/PF device is being
powered.
From this information I decided NOT too supply 3.3V to the 3.3V TARGET (pins) on the interface that I have built.
I have powered my board, the green led is on, however I measure no 3.3V present at the user switches S1,S2,and S3 (figure A-6), all is fine when USB is connected the expected 3.3V is present.
I have checked that all the 5V pins are connected. I do notice that the 3.3V TARGET from U4 on figure A-4 has to be switched on by the debug pic (TARGET_POWER_ENABLE) and that FLAGB is connected to VBUS_DEVICE_SWITCHED_SENSE.
Does this mean that I have to supply 3.3V from my circuit to the 3.3V TARGET pins in figure A-7?
Is the 3.3V TARGET switched on only when connected to USB?
Or have I got something back to front?....As I said confused, and would really be grateful for some guidance!
Message was edited by: David Cotterill-Drew