Dear all,
I am newbie on embedded system designing side. I have one confusion in mind that is I want to turn ON/OFF GPS using ATxmega128A3-AU GPIO.
GPS current consumtion is 45mA.
while ATxmega128A3-AU GPIO maximum current is 20mA.
Can i attach GPS VCC pin to GPIO pin of MCU?
I want to send high signal at GPIO to turn ON GPS and when required I will send low signal at GPIO.
Please advise with your valuable suggestions. Thank you
GPS Model is SKYLAB SKM53.
Use a small fet transistor
/Bingo
The skm53 datasheet says that it requires 5V Vcc, while the atxmega can't run at more than 3.6V, so a GPIO pin wouldn't be able to supply the skm53.
You should also note that the datasheet claims that the serial data I/O on the skm53 are 2.85V I/O signals. The datasheet doesn't say whether those signals are 3.3V or 5V tolerant, so you might need level translators, or better still, run the atxmega at 2.85V.
- S
This Thread has a diagram showing driving a load with a NFet transistor, as Bingo mentioned, above.
The schematic shows a "low side driver", the transistor is on the low (ground) side, the load is on the V+ side.
This is technically easy to wire up and test.
If there are any other signal paths from the GPS to ground, however, then this won't work. For example, if the GPS has a 1 pulse per second output tied to an LED, or a GPS locked LED, tied to ground.
The issue is that the other signal paths provide a ground connection, in addition to the switched ground connection provided by the NFet.
An option, in such a case, is to use a High Side Driver, often using a P channel transistor in a 1 or two transistor switch circuit.
JC
Hi;
I am already using this GPS with my ATxmega128A3-AU Tx pin. while I am supplying power VCC and GND pin. I am not sure about power just now.
My board is accepting 5V and I have one 3.3 V regulator. to convert it at 3.3 V.
I guess GPS is working at 5V while Tx pin of GPS is connected to GPIO of Atxmega128A3-AU.
that means GPS will not be powered up directly.I need small transistor.
