Introduction to memory-mapping Note: This section is introductory material for those who are not yet familiar with the concept of memory-mapping. If you are already experienced with memory-mapping feel free to jump to the next section. Most likely you won’t miss anything new. One of the most common ways of accessing peripherals from a CPU is memory-mapping. In short, this means that the address space of the CPU has some addresses that when accessed read/write peripheral’s registers.
Most people getting started with embedded development seem to find linker scripts just another piece of magic required to get up and running with their system. Even when they might already be familiar with memory-mapped peripherals and basic embedded concepts, the linker script and how it interacts with the GNU linker (ld) is still pretty mysterious. Today we will go through the main functions of a linker script to try to shed some light onto their operation.
In a previous blog we discussed the role of the NVIC in ARM Cortex-M microcontrollers. This peripheral will play a central role in booting our target application. First of all, we need to discuss the boot process in an ARM Cortex-M microcontroller. Boot process After Power On Reset the microcontroller assumes the NVIC table is located at address 0x00000000. The processor fetches the first two words in the NVIC table, corresponding to the top of the stack and the reset vector.
Welcome to the second entry of the Bootloader series! Today we are going to be discussing the design and basic architecture of the bootloader application. As we talked about on the last post, we are not going to be using any libraries, other than the C++ standard library in order to maximize portability and performance and limit code bloat. This means that we will be writing our own Hardware Abstraction Layer for all the peripherals and core features of the bootloader.
We are introducing a new series to the blog, containing all about bootloaders for small ARM Cortex-M microcontrollers. I hope you like it. What is a bootloader? A bootloader is a piece of firmware that takes care of booting the target application, as well as providing a mechanism to update the firmware on the field, where you don’t have the means to flash the device using more advanced hardware interfaces such as JTAG, SWD or ICSP.