title: STM32F103C8T6 (Blue pill) and Arduino nano serial communication
body: <p>I have a next code in in my Arduino nano:</p>
  
  <pre><code>#include &lt;SoftwareSerial.h&gt;
  
  SoftwareSerial mySerial(2, 3);
  void setup()
  {
    Serial.begin(115200);
    while (!Serial) {
      ; // wait for serial port to connect. Needed for Native USB only
    }
    // set the data rate for the SoftwareSerial port
    mySerial.begin(9600);
  }
  
  void loop() // run over and over
  {
    mySerial.write("Software serial from Arduino Nano\n");
    delay(500);
  }
  </code></pre>
  
  <p>If i connect the D2 and D3 to my TTL, i can read the message at 9600 baud, but if i connect the Tx->Rx and Rx->Tx to my STM32F103C8T6 (Blue pill) with a next code:</p>
  
  <pre><code>#include "stm32f103c8t6.h"
  #include "mbed.h"
  #include "USBSerial.h"
  #include "Crypto.h"
  
  int main() {
      Serial pc(PA_2, PA_3);
      Serial nano(PA_9, PA_10);
  while(1) 
      {
       //AES data here
  
       if(nano.readable()) 
          {
              printf("Nano is here!\n");
              char c[128];
              nano.gets(c, 4);
              printf("I got c line: %s \n", c);
          }
          else
          {
              printf("Nano is unreadable\n");
          }
          wait_ms(1000);
      }
  }
  </code></pre>
  
  <p>On the PA_2, PA_3 is an USB TTL, that send some encrypted data to one PC. The PA_9 and PA10 are connected to Arduino Nano, and i wish to read the data from Nano on the BluePill with this UART, but i always receive that a Nano in unreadable.
  Have try to change the Tx-Rx wires, but nothing.
  Why will not work a simultanous use of two serbials?</p>