How are variables stored in a microcontroller?
The short answer is to declare your variable with the const keyword. If your MCU actually remembers the value of your const variable (i.e. your sine computation actually works), it pretty much has to be stored in flash memory, otherwise it would be lost at the first reboot after programming.
How to store a variable in flash memory?
The short answer is to declare your variable with the const keyword. If your MCU actually remembers the value of your const variable (i.e. your sine computation actually works), it pretty much has to be stored in flash memory, otherwise it would be lost at the first reboot after programming. The long answer has to do with linker script.
How is flash memory used in microcontrollers?
With the 89C51Rx2 microcontrollers, NXP Semiconductors created a variety of 8051 derivatives with on-chip Flash memory that take best advantage of having a combination of microcontroller and Flash memory on one chip. Philips did this by providing an additional ROM area containing code for handling the Flash programming.
Why do we use flash memory for erase commands?
In the past, erase commands erased the entire memory chip – therefore to keep a working copy of that data during run-time, an application required additional memory. Since Flash memory is integrated on-chip with microcontrollers, its usage became even easier.
How is constant data stored in program memory?
These constants need to be initialized and cannot be changed at run-time. The ROM qualifier puts data into flash program memory with 3 bytes per instruction space. The address used for ROM data is a true byte address not a physical address.
How does const qualifier store variables in memory?
The CONST qualifier will place variables into flash program memory. If the keyword CONST is used before the identifier, the identifier is treated as a constant. These constants need to be initialized and cannot be changed at run-time.
https://www.youtube.com/watch?v=zZkgPUWPZ1g