NEC V850E/PH2, User Manual

Page: 973 / 1053

973 User’s Manual U16580EE3V1UD00
Chapter 22 Internal RAM Parity Check Function
The V850E/PH2 microcontroller is provided with a parity check function for the internal RAM (iRAM).
22.1 Features
• Maskable interrupt (INTPERR) on detection of parity error
• Indication of internal RAM address of detected parity error
• Indication of erroneous byte within 32-bit word
22.2 Operation
Each byte of data stored in the internal RAM is checked by its parity bit. A maskable interrupt
(INTPERR) is generated, if a parity mismatch is detected on iRAM read operation. In this case the
address of the erroneous data is latched in the RAMPADD register and the erroneous byte(s) are
indicated in the RAMERR register.
Caution: Ensure that all internal RAM data is initialized on a word (32-bit) base by a write
operation before first read access is made. It is important to initialize the whole
memory word, even if only byte or half word is used. Otherwise a parity fail may be
indicated mistakenly.