| 摘要 |
A microcontroller memory system that provides on-chip, non-volatile memory for internal data and program code storage in such a manner that all on-chip, non-volatile memory is efficiently utilized. In one embodiment, a microcontroller memory scheme allows internal program code and data stored in the non-volatile memory to be reprogrammed in place by software executing on the microcontroller or by external devices through the microcontroller's serial port. In another embodiment, data and program code stored in the internal program area can be accessed using any instruction employed to access via an internal data bus the contents of an on-chip, volatile memory. The non-volatile memory used to store the program code and internal data can be implemented with Flash memory or EEPROM. To enable compatibility with conventional 8051 controllers, a flag in a special function register is provided that indicates whether a memory access is to be into the non-volatile memory or, in the conventional manner, into internal volatile or external volatile memory used for data (as opposed to program) storage. |
