Hello everyone!
I wanted to learn about the ARM microcontrollers....about the architecture and coding. Which microcontroller should I buy? I read somewhere that I should buy the STM32 discovery board. Please help!
Which is best for you really depends on your background & experience you already have, and also how much time and effort you intend to invest.
For example, if you're already experienced in C programming, or even a higher level language like Javascript, and if you're learning this as part of a professional project (8 hours per day minus meetings & overhead) which has a deadline, you can probably go with a fairly advanced platform. ST Discovery or Nucleo would be good examples.
However, if you're a student or hobbyist, or anyone with minimal programming experience, and especially if you're doing this in your own (limited) free time without a hard goal that will force you to spend time, one of the many newer Arduino compatible boards might be a better choice. These have a greatly simplified environment and examples. The downside is the tools aren't nearly as powerful, because they're designed to be simple for beginners. The software environment tends to *not* expose you to the (complex) inner details of the ARM architecture, so to learn the deeper stuff you'd need to dig into the supplied libraries.