MC9S12G Family Reference Manual Rev.1.27
NXP Semiconductors 918
It is possible to read from P-Flash memory while some commands are executing on EEPROM memory. It
is not possible to read from EEPROM memory while a command is executing on P-Flash memory.
Simultaneous P-Flash and EEPROM operations are discussed in Section 27.4.5.
Both P-Flash and EEPROM memories are implemented with Error Correction Codes (ECC) that can
resolve single bit faults and detect double bit faults. For P-Flash memory, the ECC implementation
requires that programming be done on an aligned 8 byte basis (a Flash phrase). Since P-Flash memory is
always read by half-phrase, only one single bit fault in an aligned 4 byte half-phrase containing the byte
or word accessed will be corrected.
27.1.1 Glossary
Command Write Sequence — An MCU instruction sequence to execute built-in algorithms (including
program and erase) on the Flash memory.
EEPROM Memory — The EEPROM memory constitutes the nonvolatile memory store for data.
EEPROM Sector — The EEPROM sector is the smallest portion of the EEPROM memory that can be
erased. The EEPROM sector consists of 4 bytes.
NVM Command Mode — An NVM mode using the CPU to setup the FCCOB register to pass parameters
required for Flash command execution.
Phrase — An aligned group of four 16-bit words within the P-Flash memory. Each phrase includes two
sets of aligned double words with each set including 7 ECC bits for single bit fault correction and double
bit fault detection within each double word.
P-Flash Memory — The P-Flash memory constitutes the main nonvolatile memory store for applications.
P-Flash Sector — The P-Flash sector is the smallest portion of the P-Flash memory that can be erased.
Each P-Flash sector contains 512 bytes.
Program IFR — Nonvolatile information register located in the P-Flash block that contains the Version
ID, and the Program Once field.
27.1.2 Features
27.1.2.1 P-Flash Features
• 64 Kbytes of P-Flash memory composed of one 64 Kbyte Flash block divided into 128 sectors of
512 bytes
• Single bit fault correction and double bit fault detection within a 32-bit double word during read
operations
• Automated program and erase algorithm with verify and generation of ECC parity bits
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