MPC555
/
MPC556
CDR MoneT FLASH EEPROM
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
19-17
During reset the HC bit (“has configuration,” bit 20) and the USIU configure the CMF
EEPROM module to provide CMFCFIG. If HC = 0 and the USIU requests internal con-
figuration during reset the reset configuration word will be provided by CMFCFIG.
The default reset state of the CMFCFIG after an erase operation of the CMF module
A block 0 is no configuration word available (HC = 1).
19.4 Array Read Operation
The CMF EEPROM array is available for read operation under most conditions while
the device is powered up. Reads of the array are not allowed under any of the following
conditions:
• During master or soft reset
• ACCESS = 0 and CENSOR[0:1] = 11 or 00
• While the CMF EEPROM is disabled
During programming and erase operations, while the high voltage is applied to the ar-
ray, the BIU does not acknowledge a CMF array read. At certain points, as defined in
the program or erase sequence, reading the array results in a margin read. These mar-
gin reads return the status of the program or erase operation and not the data in the
array.
The type of CMF EEPROM array read is determined by comparing the address of the
requested information with the address of the read page buffers. If the requested ad-
dress is not within one of the read page buffers or if the read page buffer has been
made invalid, an off-page read results. This read updates the read page buffer address
of the selected array block, copies the information from the array into the read page
buffer, and drives a word onto the data bus. The off-page read requires a minimum of
two clocks, while margin off-page reads require additional clocks.
If the address of the requested information is within the address ranges of either of the
read page buffers, an on-page read is performed. This requires one clock to transfer
information from the read page buffer onto the data bus. See section
for more information on array accesses.
CMFCFIG
— Hard Reset Configuration Word
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
EARB
IP
BDRV
BDIS
BPS
RESERVED
DBGC
DBPC ATWC
EBDF
Re-
served
LSB
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
PRPM
SC
ETRE
FLEN
EN_
COMP
EXC_
COMP
Reserved
ISB
DME
F
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sc
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S
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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