ColdFire Flash Module (CFM)
MCF52110 ColdFire® Integrated Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
17-9
Preliminary
All CFMCLKD register bits are readable, while bits [6:0] write once and bit 7 is not writable.
17.3.3.3
CFMSEC — CFM Security Register
The CFMSEC register is used to store the flash security word and CFM security state.
CFMSEC register bits [31:30,15:0] are readable, while remaining bits read 0 and all bits are not writable.
Table 17-5. CFMCLKD Field Descriptions
Field
Description
7
DIVLD
Clock Divider Loaded
1 = CFMCLKD register has been written to since the last reset.
0 = CFMCLKD register has not been written.
6
PRDIV8
Enable Prescaler by 8
1 = Enables a prescaler to divide the internal flash bus clock by 8 before feeding into the clock divider.
0 = The internal flash bus clock is directly fed into the clock divider.
5-0
DIV
Clock Divider Bits
The combination of PRDIV8 and DIV effectively divides the internal flash bus clock down to a frequency
of 150 KHz - 200 KHz. The internal flash bus clock frequency range is 150 KHz less than the internal flash
bus clock which is less than 102.4 MHz.
The CFMCLKD register bits PRDIV8 and DIV must be set with appropriate values before programming
or erasing the CFM flash memory
Section 17.4.2.3.1, “Writing the CFMCLKD Register
.”
IPSBAR
Offset: 0x1D_0008 (CFMSEC)
Access: User read/write
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
R KEYEN SECSTAT
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
F
1
1
Reset state loaded from flash configuration field during reset.
-
2
2
Reset state determined by security state of CFM.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
SEC
W
Reset
F
F
F
F
F
F
F
Figure 17-6. CFM Security Register (CFMSEC)
Table 17-6. CFMSEC Field Descriptions
Field
Description
31
KEYEN
Enable backdoor key access to unlock security
1 = Backdoor key access to flash module is enabled.
0 = Backdoor key access to flash module is disabled.
30
SECSTAT
Flash memory security status
1 = Flash security is enabled.
0 = Flash security is disabled.
