add a pinout diagram of the blue pill

doc/Quickstart.md

@@ -317,9 +317,16 @@ $ xargo rustc --target $TARGET --release -- -Z print-link-args
 
 ### Flash and debug
 
-To flash the program into the microcontroller we must first start OpenOCD. OpenOCD will connect to
-the SWD programmer (built into the NUCLEO-F401RE board; for the blue-pill you'll need an external
-one) and start a GDB server.
+To flash the program into the microcontroller we must first connect the device to our laptop. If you
+are using a NUCLEO-F401RE you only to connect a USB cable. If you are using the blue-pill you'll
+have to connect a external SWD programmer. The pinout of the blue-pill is shown below ;
+you'll have to at least connect the GND, SWDIO and SWCLK pins. If you want to power the blue-pill
+using the SWD programmer then also connect the 3V3 *or* the 5V pin.
+
+![blue-pill pinout](http://wiki.stm32duino.com/images/a/ae/Bluepillpinout.gif)
+
+Then we have to start OpenOCD. OpenOCD will connect to the SWD programmer (the NUCLEO-F401RE board
+has a built-in one) and start a GDB server.
 
 ``` console
 $ # for the blue-pill