Dear, I just received my jeenode usb.
connected to PC, without any external HW: they are working , no problem.
The question is the following: on the board I read +3V on the different ports, but if I measure I have around 4.7V, thing that I found very strange, also looking to the schematic.
same situation is present for all the nodes I have
did anybody find the same behavious, is it normal or am I missing something?
question on 3.3V on the jeenode usb
(5 posts) (2 voices)-
Posted 01/02/2010 19:32:36
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The PWR pin should be around 4.7 .. 5V, the +3V pin should be 3.3V. Is that what you're seeing?
Posted 01/02/2010 20:25:02 -
I was expecting:
pin +3V --> 3.3V
pin PWR --> 5Vbut what I measure with multimeter is:
pin +3V --> 4.7V
pin PWR --> 5VConfiguration:
no external HW connected, only usb cable to PC
demoRF SW downloaded
system is operational and communicatethe situation is the same for the different Jeenodes I have.
is this normal?
Posted 02/02/2010 08:20:05 -
Doesn't sound right. Can you do one more test? Set one of the port DIO pins to "1" and measure it's signal. If it is around 3.3V then the board is probably ok but the 3.3V regulator is bad. If it is higher then the FTDI chip is supplying 5V to the board and everything is off. Either way it's odd - please contact me by email and we'll work something out.
Posted 02/02/2010 08:59:51 -
WHOOOOOPS...
There is a design error in the JeeNode USB v2 - the on-board MCP1703 voltage regulator has been hooked up backwards. Consequence: all +3V pins on the port headers will deliver 4.7V to any attached plugs, instead of the required 3.3V.
The board itself functions properly, because all on-board components are supplied via the 3.3V from the FTDI chip.
I will write a post about this. Thank you Cristiano for persevering and doing all the tests.
Posted 02/02/2010 12:58:18