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April 3, 2012
about 4 years ago
Sorry, I should have been clearer on my setup:
I have two different Venus Modules here 634 (10 Hz) and 638 (20 Hz). I connect VCC from PackageTracker (PT) to VBAT and via a transistor to 3.3V at the Venus module. I’m using the enable pin from PT to trigger the transistor which either shuts off or turns on VCC connected to 3.3V, hence putting the Venus in and out of sleep mode.
I use another transistor to shut down power to Venus completely to reset it. This transistor disconnects the GND between PT and Venus and is triggered by the reset pin from PT. It’s only necessary because the reset button on PT doesn’t disconnect VCC and so without this transistor the Venus module wouldn’t reset but just go into sleep mode shortly.
This setup works perfectly with the Venus 634 but refuses to reset with the 638 because 638 keeps the settings although all power is cut, because of, allegedly, C5.
Since your working on the next PT: I got the PT logging reliably the 10 Hz of the 634 and even the 20 Hz of 638 seems to work. If you’re interested in what I’ve done with the PT firmware I’ll be happy to share my knowledge with you, but be patient, since I have other things at hand and am on holiday the next week.
Thanks for the advice. I’m not using (and am not planning to use) the Venus without the power regulator (I want it to live!).
I’m using both connection pins because I want to be able to use the sleep mode of the Venus. I know that it’s not working out of the box with the PT Firmware due to a different logic regarding sleep mode (EM408 vs. Venus). So I put a small PCB on top of the Venus with a transistor on it which shuts down power to the Venus. Maybe I just put another transistor on this PCB which discharges C5 every time I shut down power completely instead of removing C5.
Thanks again for your help and advice!
Update: I let it rest overnight and now the settings I changed are gone, so I’m quite sure it is the Capacitor, so can I remove it?
I have two problems with my Venus Board which I suspect to be connected.
First of all my setup:
I have disconnected the BAT jumper and am feeding the Venus (both VBAT and 3.3V) from a 3.7 V LiPo battery which works just fine (to be precise I’m using the PackageTracker).
Problem nr. 1 (which really isn’t one but it occurred to me as strange):
When I measure the resistance between the BAT jumper pad, which is connected through the diode and the resistor to VBAT, and the actual VBAT line (either pin directly at Venus module or pin header) I don’t measure anything. Since there is a diode involved I tried both directions which didn’t help.
Do I have a faulty device?
Prblem nr. 2 (the real problem):
I want the Venus to reset to default settings the moment I remove power from both VBAT and 3.3V. So when I configure it I write all the settings to SRAM only (not to flash!!!) but when I disconnect the power source it keeps the settings nevertheless (even if I disconnect all the wires).
Is this because of capacitor nr. 5?
If it is because of capacitor nr. 5, can I just remove it?
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