MC68HC908AS60ACFN FREESCALE [Freescale Semiconductor, Inc], MC68HC908AS60ACFN Datasheet - Page 96

• Manufacturer Part Number: MC68HC908AS60ACFN
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

EEPROM-2 Memory
EEDIVSECD — EEPROM-2 Divider Security Disable
EEDIV[10:0] — EEPROM-2 timebase prescaler
Where the result inside the bracket is rounded down to the nearest integer value
For example, if the reference frequency is 4.9152MHz, the EE2DIV value is 172
7.5.5 EEPROM-2 Timebase Divider Nonvolatile Register
The 16-bit EEPROM-2 timebase divider nonvolatile register consists of two 8-bit registers: EE2DIVHNVR
and EE2DIVLNVR. The contents of these two registers are respectively loaded into the EEPROM-2
timebase divider registers, EE2DIVH and EE2DIVL, after a reset.
These two registers are erased and programmed in the same way as an EEPROM-2 byte.
96
This bit enables/disables the security feature of the EE2DIV registers. When EE2DIV security feature
is enabled, the state of the registers EE2DIVH and EE2DIVL are locked (including EEDIVSECD bit).
The EE2DIVHNVR and EE2DIVLNVR nonvolatile memory registers are also protected from being
erased/programmed.
These prescaler bits store the value of EE2DIV which is used as the divisor to derive a timebase of
35μs from the selected reference clock source (CGMXCLK or bus block in the CONFIG-2 register) for
the EEPROM-2 related internal timer and circuits. EEDIV[10:0] bits are readable at any time. They are
writable when EELAT = 0 and EEDIVSECD = 1.
The EE2DIV value is calculated by the following formula:
1 = EE2DIV security feature disabled
0 = EE2DIV security feature enabled
EE2DIV= INT[Reference Frequency(Hz) x 35 x10
Figure 7-7. EEPROM-2 Divider Nonvolatile Register High (EE2DIVHNVR))
Address:
Address:
Figure 7-8. EEPROM-2 Divider Nonvolatile Register Low (EE2DIVLNVR)
Programming/erasing the EEPROM with an improper EE2DIV value may
result in data lost and reduce endurance of the EEPROM device.
Reset:
Reset:
Read:
Read:
Write:
Write:
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
EEDIVS-
EEDIV7
$FF70
$FF71
ECD
Bit 7
Bit 7
R
= Reserved
EEDIV6
R
6
6
EEDIV5
R
5
5
Unaffected by reset; $FF when blank
Unaffected by reset; $FF when blank
NOTE
EEDIV4
R
4
4
EEDIV3
-6
R
3
3
+0.5]
EEDIV10
EEDIV2
2
2
EEDIV9
EEDIV1
1
1
Freescale Semiconductor
EEDIV8
EEDIV0
Bit 0
Bit 0