adding markdown file

+ minor correction to code

docs/udp_broadcast.md

@@ -0,0 +1,109 @@
+# UDP broadcast
+
+## Introduction
+
+The UDP broadcast code is used to handle incoming UDP datagrams.
+there are currently 2 types of datagrams it processes:
+- broadcasts: "Where are you?v1.0", replies with current owner details.
+- change of details: "func1:name: ..., surname: ...", replies with changed owner details.
+
+It also writes the current owner's name on the screen and updates it everytime it's changed.
+
+## Table of contents
+- [Introduction](#introduction)
+- [Table of contents](#table-of-contents)
+- [Usage of UDP broadcast](#usage-of-udp-broadcast)
+  - [Initialization of UDP broadcast](#initialization-of-udp-broadcast)
+  - [Initialization of UDP connection](#initialization-of-udp-connection)
+  - [Owner details interface](#owner-details-interface)
+    - [Setting owner details](#setting-owner-details)
+    - [Getting owner details](#getting-owner-details)
+
+## Usage of UDP broadcast
+### Initialization of UDP broadcast
+The 'udp_broadcast_init(uint16_t x_pos, uint16_t y_pos)' function does 4 things:
+1. It initializes the coördinates of where the owner's name has to be written on the LCD.
+2. [It initializes the UDP connection](#initialization-of-udp-connection)
+3. It initializes the owner's details with a default name.
+4. Returns the error value of [udp_broadcast_connection_init()](#initialization-of-udp-connection). This way the user can use some code to check whether the "connection" was initialized correctly. 
+```c
+#include "UDP_broadcast.h'
+
+...
+
+void main(void){
+    ...
+    if (udp_broadcast_init(270,255) != ERR_OK){
+      ...
+  }
+    ...
+}
+```
+
+### Initialization of UDP connection
+The 'udp_broadcast_connection_init()' funciton does 2 things:
+1. Initializes the UDP "connection" so that incoming datagrams can be processed and replied to. It binds to port 64000 and listens to every IP-address in the local network.
+2. returns the LWIP error code so that [err_t udp_broadcast_init(uint16_t x_pos, uint16_t y_pos)](#initialization-of-udp-broadcast) knows the "connection" is initializes correctly
+
+This function can be used seperately from [err_t udp_broadcast_init(uint16_t x_pos, uint16_t y_pos)](#initialization-of-udp-broadcast), this gives the possibility to try "connecting" again after the first time failed.
+```c
+#include "UDP_broadcast.h'
+
+...
+
+void main(void){
+    ...
+    if (udp_broadcast_init(270,255) != ERR_OK || udp_broadcast_connection_init() != ERR_OK){
+      ...
+  }
+    ...
+}
+
+```
+### Owner details interface
+The interface to ask for the owner's details and change them is a modified version of the [Qt application](https://github.com/wimdams/Device_finder) Wim Dams build. His only has the functionality to ask for the owner's details.
+
+Just because the owner's details might want to be used in other code, some functions have been written for obtaining these in the STM32 code aswell.
+#### Setting owner details
+THe 'udp_broadcast_set_owner_details(const char* , const char*)' function does 2 things:
+1. Set the owner details, the order of the parameters is: name, surname
+2. Return 1 if the owner's details have been set correctly and 0 if not.
+```c
+#include "UDP_broadcast.h'
+
+...
+
+void main(void){
+    ...
+  if (!udp_broadcast_set_owner_details("Joran", "Van Nieuwenhoven")){
+      ...
+  }
+    ...
+}
+```
+#### Getting owner details
+There are 3 functions:
+- udp_broadcast_get_owner_details_name(): returns the owner's name.
+- udp_broadcast_get_owner_details_surname(): returns the owner's surname.
+- udp_broadcast_get_owner_details_reply(): returns what would be replied to a UDP broadcast with datagram "Where are you?v1.0".
+
+```c
+#include <string.h>
+#include "UDP_broadcast.h'
+
+...
+
+void main(void){
+    ...
+    char name[20];
+    char surname[20];
+    char reply[120];
+
+    strncp(name,udp_broadcast_get_owner_details_name(),sizeof(name));
+
+    strncp(surname,udp_broadcast_get_owner_details_surname(),sizeof(surname));
+
+    strncp(reply,udp_broadcast_get_owner_details_reply(),sizeof(reply));
+    ...
+}
+```

project/Core/Src/main.c

@@ -127,7 +127,7 @@ int main(void)
   llfs_init();
 
   // Initialize the UDP broadcast service
-  if (udp_broadcast_init(270,255) != ERR_OK && udp_broadcast_connection_init() != ERR_OK){
+  if (udp_broadcast_init(270,255) != ERR_OK || udp_broadcast_connection_init() != ERR_OK){
       LOG_WARN(TAG,"error initializing udp connection");
   }
   if (!udp_broadcast_set_owner_details("0123456879012345678", "default")){