Interface Chip Market

 

What Makes a Software Application?

Much of the OTA update process is the act of transferring the new software from the server to the client. The software is transferred as a sequence of bytes, after it has been converted into a binary format from the source format. The conversion process compiles the source code files (for example, c, cpp), links them together into an executable file (for example, exe, elf), and then the executable is converted into a portable binary file format (for example, bin, hex). At a high level, these file formats contain a sequence of bytes that belong at a specific address of memory in the microcontroller. Typically, we conceptualize the information being sent over a wireless link as data, such as a command to change the system’s state or sensor data collected by the system. In the case of the OTA update, the data is the new software in binary format. In many cases, the binary file will be too large to send in a single transfer from the server to the client, meaning that the binary file will need to be placed into separate packets, in a process called packetizing. To visualize this process better, Figure 2 demonstrates how different versions of the software will produce different binary files, and thus different packets to be sent during the OTA update. In this simple example, each packet contains 8 bytes of data, with the first 4 bytes representing the address in the client’s memory to store the next 4 bytes.