AN2400 Freescale Semiconductor / Motorola, AN2400 Datasheet - Page 33

• Manufacturer Part Number: AN2400
• Description: HCS12 NVM Guidelines
• Manufacturer: Freescale Semiconductor / Motorola

Illegal EEPROM
Operations
MOTOROLA
The command register, EEPROM address register and EEPROM data
registers are buffered to allow pipelined programming. Pipelined programming
reduces the programming time by allowing the next address, data and
command to be loaded while the current command is still executing.
The general command sequence is described in
Sequence.
following initialisation sequence:
The ACCERR flag will be set during the command write sequence if any of the
following illegal operations are performed causing the command write
sequence to immediately abort:
The ACCERR flag will not be set if any EEPROM register is read during the
command sequence.
If the EEPROM array is read during execution of an algorithm (i.e. CCIF bit in
the ESTAT register is clear) the read will return non valid data and the
ACCERR flag will not be set.
When an ACCERR flag is set in the ESTAT register the Command State
Machine is locked. It is not possible to launch another command until the
ACCERR flag is cleared.
10. A “0” is written to the CBEIF bit in the ESTAT register.
1. If the EDIVLD bit is clear, initialise the ECLKDIV register.
2. Verify that all ACCERR and PVIOL flags in the ESTAT register are clear.
1. Writing to the EEPROM address space before initializing ECLKDIV.
2. Writing a misaligned word or a byte to the valid EEPROM address
3. Writing to the EEPROM address space while CBEIF is not set.
4. Writing a second word to the EEPROM address space before executing
5. Writing to any EEPROM register other than ECMD after writing a word
6. Writing a second command to the ECMD register before executing the
7. Writing an invalid user command to the ECMD register in user mode.
8. Writing to any EEPROM register other than ESTAT (to clear CBEIF)
9. If the microcontroller enters STOP mode and a program or erase
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a program or erase command on the previously written word.
to the EEPROM address space.
previously written command.
after writing to the command register, ECMD.
command is in progress, the command is aborted and any pending
command is aborted.
Flash/EEPROM Command Sequence
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HCS12 NVM Guidelines
Flash/EEPROM Command
must be preceded with the
AN2400/D
EEPROM
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