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MPC555
/
MPC556
CDR MoneT FLASH EEPROM
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
19-10
Table 19-6 CMFCTL Bit Descriptions
Bit(s)
Name
Description
0
HVS
High voltage status. During a program or erase pulse this bit is set while the pulse is active or
during recovery. The BIU does not acknowledge an access to an array location if HVS = 1. While
HVS = 1, SES cannot be changed. This bit is read only; writes have no effect.
0 = Program or erase pulse is not applied to the CMF array or shadow information
1 = Program or erase pulse is applied to the CMF array or shadow information
1
—
Reserved
2:4
SCLKR
System clock range. These bits are write protected by the SES bit. Writes to CMFCTL do not
change SCLKR[0:2] if SES = 1. The default reset state of SCLKR[0:2] = 000 for a clock scaling
of 1.
000 = Clock scaling of 1 (Not for Customer use.)
001 = Clock scaling of 1
010 = Clock scaling of 3/2
011 = Clock scaling of 2
100 = Clock scaling of 3
101 = Clock scaling of 4
110 = Reserved
111 = Reserved
Refer to
for instructions on selecting a clock scaling factor.
5
—
Reserved
6:7
CLKPE
Clock period exponent. The CLKPE, CSC, and PE fields determine the value of the exponential
clock multiplier, N. Refer to
19.7.4 Exponential Clock Multiplier
for details.
The CLKPE bits are write protected by the SES bit. Writes to CMFCTL will not change CLKPE
if SES = 1.The default reset state of CLKPE is 00.
8
—
Reserved
9:15
CLKPM
Clock period multiple. This field determines the linear clock multiplier, M, according to the follow-
ing equation:
M = 1 + CLKPM[0:6]
The CLKPM bits are write protected by the SES bit. Writes to CMFCTL will not change CLKPM
if SES = 1. The reset state of CLKPM = 0, for a multiplier of 1. Refer to
for more information.
16:23
BLOCK
[0:7]
Block program and erase select. The CMF EEPROM array blocks that are selected to be pro-
grammed or erased are the blocks for which BLOCK[M] = 1.
Bit 16 controls block 0 and bit 23 controls block 7. On the 192-Kbyte array (Flash Module B),
blocks 6 and 7 are not available, but these bits need to be set when doing a clear censor oper-
ation.
Warning: The block bit must be set only for the blocks currently being programed. If the block
bits are set for blocks that are not being programmed, the contents of the other blocks could be
disturbed.
The BLOCK[0:7] bits are write protected by the SES bit. Writes to CMFCTL will not change
BLOCK[0:7] if SES = 1. BLOCK[0:7] default reset state is 0x00, not selected for program or
erase.
0 = Array block M is not selected for program or erase
1 = Array block M is selected for program or erase
24
—
Reserved
25
CSC
Censor set or clear. CSC configures the CMF EEPROM for setting or clearing the CENSOR bits.
If CSC=1 then CENSOR is configured for setting if PE = 0 or clearing if PE = 1. For more infor-
mation on setting or clearing the CENSOR bits see section
19.8.4 Setting and Clearing Cen-
.
The CSC bit is write protected by the SES bit. Writes to CMFCTL will not change CSC if SES = 1.
0 = Configure for normal operation (default value)
1 = Configure to set or clear the CENSOR bits
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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