Reverse Microchip PIC18F2220 MCU Flash Program
During interrupts and subroutine calls, the return address PC is stored on the Stack. The Stack is effectively allocated in the general data SRAM, and consequently the Stack size is only limited by the total SRAM size and the usage of the SRAM from Reverse Microchip PIC18F2220 MCU Flash Program. After reset the Stack Pointer (SP) points to the highest address in the internal SRAM.
The SP is read/write accessible in the I/O memory space, enabling easy implementation of multiple stacks or stack areas. The data SRAM can easily be accessed through the five different addressing modes supported in the AVR CPU.The AVR architecture has two main memory spaces, the Program Memory and the Data Memory.
In addition, the XMEGA A3 features an EEPROM Memory for non-volatile data storage. All three memory spaces are linear and require no paging. The available memory size configurations are shown in ”Ordering Information” on page 2. In addition each device has a Flash memory signature row for calibration data, device identification, serial number etc. Non-volatile memory spaces can be locked for further write or read/write operations.
This prevents unrestricted access to the application software. The XMEGA A3 devices contains On-chip In-System Programmable Flash memory for program storage, see Figure 7-1 on page 10. Since all AVR instructions are 16- or 32-bits wide, each Flash address location is 16 bits. The Program Flash memory space is divided into Application and Boot sections.
Reverse Microchip PIC18F2220 MCU Flash Program
Both sections have dedicated Lock Bits for setting restrictions on write or read/write operations. The Store Program Memory (SPM) instruction must reside in the Boot Section when used to write to the Flash memory before the code.
A third section inside the Application section is referred to as the Application Table section which has separate Lock bits for storage of write or read/write protection. The Application Table section can be used for storing non-volatile data or application software from MCU CRACK.