No voltage on pins of SD card when powered

Hello ,

I am using an Arduino promini 3.3V and an sd card breakout board .(both mounted on a pcb)

When I supply power , the red light on the micro controller lights up showing that it is powered , but the green light does not light up.

I checked the connections with a multimeter and all the pins (10,11,12,13) from the micro controller to the SD card breakout board are connected but there is no voltage drop through the pins.

Can anyone please tell me what the problem might be and a solution regarding this?

I have connected :
Promini SD card breakout board.
10 - CS
11 -D1
12 -D0
13 -CLK

Link for micro sd card breakout board - MicroSD card breakout board+ : ID 254 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits
Promini - Arduino Pro Mini 328 - 3.3V/8 MHz : ID 2377 : $11.95 : Adafruit Industries, Unique & fun DIY electronics and kits

Thank you

You need to connect ground and 5V too... Its not clear from the description if you can
just provide 3.3V to the 3V pin to power it (it has an on-board regulator). Note that
SD cards need a lot of current - 150mA is claimed, I suspect some fast SD cards need more.

[ and how can voltage flow? its a difference in potential between 2 points in a circuit ]

I am providing just 3.3 V to 3 V pin to power it. It worked before . I am unable to figure out whatthe problem is now.

Sorry for using the wrong technical term.

It would be much better if you would have all the problems with your project in one thread.
Because one thing might be related to the other.

A ProMini has a 150mA regulator.
That's total current for everything, including the MCU.
It seems you are already powering several sensors/LEDs, so there might not be enough current left for the SD card. I also saw a battery and another device between batt and Vin of the ProMini in another thread.
The regulator on the ProMini is very small, and can easilly overheat if V-in is too high.
Give us the full picture if you want proper advice. All in one thread.
Leo..

Hello,

I have powered the promini 3.3V with a 3.7 V battery. It is connected to the raw pin of microcontroller.
The micro controller also has a 3 V sensor , DS3231 and a SD card breakout board connected to it.
It also has a external reset button and a push button connected to pin 7.
I am using 4k7 pull ups for I2C pins and a 100 ohm resistor for the led.
I have a push button connected to the battery to switch ON/OFF the power.
I have attached a schematic below.
All the other pins get sufficient voltage but the pins 10,11,12,13 do not.

Please let me know if there is any other information I can provide you with.

dpoornima:
I have powered the promini 3.3V with a 3.7 V battery. It is connected to the raw pin of microcontroller.

What is U1, between the battery and V-in (RAW).

Better to post a screenshot than a picture of the screen.
Use File>Export>Image in Eagle.
Leo..

This is the link for the power button I am using.

The in pin is connected to + of battery,
ground to - of battery.
Out to Raw.

I Cannot currently access the computer. Sorry.