user29222: I recently purchased a 5V arduino pro mini that I now wish to connect to a BLE device.
I firstly tried the BLE device with my Uno board and it worked very well! However when I now try to use it on my mini it does not start.
This is my wiring:
First I connect the pro mini to the uno in order to upload the code looking like this:

Arduino Mini Pro to Arduino Uno
RX --> TX
TX --> RX
VCC --> 5v
GND --> GND
RST --> RST

Then I wire the mini to my BLE device (https://learn.adafruit.com/getting-started-with-the-nrf8001-bluefruit-le-breakout/hooking-everything-up):

Arduino Mini Pro to BLE nRF8001
13 --> SCK
12 --> MISO
11 --> MOSI
10 --> REQ
9 --> RST
2 --> RDY
GND --> GND
VCC --> VIN

When I connect this setup to the computer the arduino uno starts and also the pro mini (both has LED lights on). I upload a simple test code that worked when i tried it with the uno but the BLE device does not respond (it seems like it does not turn on) when i use it with the pro mini.
Any idea what might be wrong? I have my board put as: Arduino Pro or Pro Mini, ATmega328 (5V, 16 MHz).
Thanks a ton!! :)

user13432: 
This is my wiring: First I connect the pro mini to the uno in order to upload the code looking like this:

Arduino Mini Pro to Arduino Uno

RX --> TX
TX --> RX
VCC --> 5v
GND --> GND
RST --> RST

How would this work? The bootloader in the Uno and Mini Pro will both try to reply. You need a FTDI or a USB-to-UART module instead of the Uno. Alternatively, start by programming the Uno to act as a USB-to-UART converter using Serial and SoftwareSerial. 
Cheers!

29222: <p>I recently purchased a 5V arduino pro mini that I now wish to connect to a BLE device.</p>

<p>I firstly tried the BLE device with my Uno board and it worked very well! However when I now try to use it on my mini it does not start.</p>

<p>This is my wiring:
First I connect the pro mini to the uno in order to upload the code looking like this:</p>

<ol>
<li><p>Arduino Mini Pro to Arduino Uno</p></li>
<li><p>RX --> TX</p></li>
<li>TX --> RX</li>
<li>VCC --> 5v</li>
<li>GND --> GND</li>
<li>RST --> RST</li>
</ol>

<p>Then I wire the mini to my BLE device (<a href="https://learn.adafruit.com/getting-started-with-the-nrf8001-bluefruit-le-breakout/hooking-everything-up" rel="nofollow noreferrer">https://learn.adafruit.com/getting-started-with-the-nrf8001-bluefruit-le-breakout/hooking-everything-up</a>):</p>

<ol>
<li><p>Arduino Mini Pro to BLE nRF8001</p></li>
<li><p>13 --> SCK</p></li>
<li>12 --> MISO</li>
<li>11 --> MOSI</li>
<li>10 --> REQ</li>
<li>9 --> RST</li>
<li>2 --> RDY</li>
<li>GND --> GND</li>
<li>VCC --> VIN</li>
</ol>

<p>When I connect this setup to the computer the arduino uno starts and also the pro mini (both has LED lights on). I upload a simple test code that worked when i tried it with the uno but the BLE device does not respond (it seems like it does not turn on) when i use it with the pro mini.</p>

<p>Any idea what might be wrong? I have my board put as: Arduino Pro or Pro Mini, ATmega328 (5V, 16 MHz).</p>

<p>Thanks a ton!! :)</p>
 13432: <blockquote>
  <p>This is my wiring: First I connect the pro mini to the uno in order to upload the code looking like this:</p>
</blockquote>

<pre><code>Arduino Mini Pro to Arduino Uno

RX --&gt; TX
TX --&gt; RX
VCC --&gt; 5v
GND --&gt; GND
RST --&gt; RST
</code></pre>

<p>How would this work? The bootloader in the Uno and Mini Pro will both try to reply. You need a FTDI or a USB-to-UART module instead of the Uno. Alternatively, start by programming the Uno to act as a USB-to-UART converter using Serial and SoftwareSerial. </p>

<p>Cheers!</p>
