Integrated Memory Elements On Microcontroller Devices

All microcontroller (MCU) devices have a Central Processing Unit (CPU), a Clock, Program Memory, Modifiable Memory and Input/Output Lines. Many microcontrollers operate in a “single chip” mode where there is no reliance on external memory elements. Others require only random access memory (RAM) or read only memory (ROM) to operate. It is possible to have a microcontroller with only RAM provided there is some means to download a program into the RAM and then direct the CPU to start program execution at some entry point in the program. It is also possible to have a microcontroller with only ROM. Of course, there would be no ability to use a “stack” oriented program which uses subroutine calls or interrupt routines because ROM cannot be written to by the program.Also, data manipulation would be limited to the MCU’s internal registers. For the purposes of this paper, it will be assumed that there is sufficient ROM and RAM available to the microcontroller device so that meaningful programs can be stored on t h e chip as well has allowing appropriate data manipulation. The purpose of this paper is to discuss novel uses of memory as well as new memory types, such as Electrically Erasable Programmable Read Only Memory (EEPROM), that have successfully been integrated into microcontroller chips. The first section of this paper will deal with new memory types and the latter sections will discuss novel uses of memory. Conventional static RAM and ROM will only be mentioned here for the sake of completeness.