Code Flash Self-Programming - NEC V850ES/F 3-L Series User Manual

Flash Memory Chapter 7

7.3 Code Flash Self-Programming

This V850 microcontroller supports a flash macro service that allows the user
program to rewrite the internal flash memory by itself.
By using this flash macro service and a self-programming library, provided by
NEC, the user's program is able to rewrite the flash memory with data,
transferred in advance to the internal RAM.
Thus the user program can be upgraded and constant data can be rewritten in
the field.
internal RAM
User's re-programming routine
Self-programming library
Flash function execution Flash information
Flash macro service
Erase, write
Flash memory
Figure 7-13 Concept of self-programming
During self-programming access to the flash memory is not possible. Thus
program execution is only possible by instruction fetching from internal RAM.
Consequently the instructions of user re-programming software routines, which
shall remain in operation during the self-programming procedure, must be
copied from the flash memory to the internal RAM prior to activating the self-
programming. Since interrupt processing by using the interrupt vectors in the
flash memory is also impossible during self-programming, a special feature is
provided to re-route interrupt acknowledges to the internal RAM (refer to
"Interrupt handling during flash self-programming" on page 283).
It is recommended to refer to the application note "Self-Programming"
(document nr. U16929EE) for comprehensive information concerning flash
self-programming. This document explains also the functions of the self-
programming library. The latest version of this document and the library can be
loaded via the URL
http://www.eu.necel.com
User's Manual U18743EE1V2UM00 277