MMC2107 Datasheet, PDF (203/618 Pages) –

Freescale Semiconductor, Inc.
Non-Volatile Memory FLASH (CMFR)
Registers and Memory Map
Once EHV is set, SES cannot be changed; attempts to read or write
the array or CMFRRC cause bus errors.
The default reset state of EHV disables program or erase pulses
(EHV = 0). A master reset while EHV = 1 terminates the high-voltage
operation and the CMFR generates the required sequence to disable
the high voltage without damage to the high-voltage circuits.
1 = Program/erase pulse enabled
0 = Program/erase pulse disabled
9.7.2 Array Addressing
Information in the array is accessed in 32-byte pages. Two read page
buffers are aligned to the low order addresses. The first page buffer is
for the lower array blocks. The second page buffer is for the higher array
blocks. Access time of information in the read page buffers is one system
clock. Access time for an off-page read is two system clocks. To prevent
the BIU from accessing an unnecessary page from the array, the CMFR
monitors the address to determine if the required information is within
one of the two read page buffers and the access is valid for the module.
This strategy allows the CMFR to have a 2-clock read for an off-page
access and a 1-clock read for an on-page access.
Writing to the array while not in a program/erase sequence causes a bus
error.
9.7.2.1 Read Page Buffers
The two 32-byte read page buffers are fully independent and are located
in two separate read sections of the array. The BIU monitors the status
and address of each page buffer. The status of the read page buffers are
usually valid, but are made invalid by these operations:
• Reset
• Programming write
• Erase interlock write
• Setting the EHV bit
• Clearing the SES bit
• Setting or clearing the SIE bit
• Exiting stop mode
• Exiting disable mode
• Exiting boot mode
MMC2107 – Rev. 2.0
MOTOROLA
Non-Volatile Memory FLASH (CMFR)
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Technical Data
203