arhi
Member
Hi,
I have a strange "problem" ... now .. let us ignore rest of the circuit, the important part is:
GND from USB connector is connected to GND on the board
GND from the regulated 5V source is connected to GND on the board
1 (mclr) is pushed up to vcc with 10K
3 (RA1) is connected to 5V from USB connector (so I can detect when usb is connected)
8,19 (VSS) is connected to the GND on the board
20 (VDD) is connected to regulated 5V source
RA1 is set as digital input
now, I connect 5V regulated and everything works ok, now I connect USB connector and all works ok .. communication works etc etc...
I disconnect 5V regulated - AND EVERYTHING WORKS !!!!
I disconnect USB, (so nothing is connected to device) and device shuts down
I connect USB only - AND EVERYTHING WORKS...
on board is also one 3V stabilizer (using 5V as a source), few i2c devices ...
the only way USB 5V can power up all this is trough PIC !! like RA1 and VDD pin's are shorted out ?!?!?!
anyone?
I have a strange "problem" ... now .. let us ignore rest of the circuit, the important part is:
GND from USB connector is connected to GND on the board
GND from the regulated 5V source is connected to GND on the board
1 (mclr) is pushed up to vcc with 10K
3 (RA1) is connected to 5V from USB connector (so I can detect when usb is connected)
8,19 (VSS) is connected to the GND on the board
20 (VDD) is connected to regulated 5V source
RA1 is set as digital input
now, I connect 5V regulated and everything works ok, now I connect USB connector and all works ok .. communication works etc etc...
I disconnect 5V regulated - AND EVERYTHING WORKS !!!!
I disconnect USB, (so nothing is connected to device) and device shuts down
I connect USB only - AND EVERYTHING WORKS...
on board is also one 3V stabilizer (using 5V as a source), few i2c devices ...
the only way USB 5V can power up all this is trough PIC !! like RA1 and VDD pin's are shorted out ?!?!?!
anyone?