XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 105

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

MC68HC908AZ60A — Rev 2.0
MOTOROLA
NOTE:
EEDIVSECD — EEPROM-1 Divider Security Disable
EEDIV[10:0] — EEPROM-1 timebase prescaler
The EE1DIV value is calculated by the following formula:
Where the result inside the bracket is rounded down to the nearest
integer value
For example, if the reference frequency is 4.9152MHz, the EE1DIV
value is 172
Programming/erasing the EEPROM with an improper EE1DIV value
may result in data lost and reduce endurance of the EEPROM device.
This bit enables/disables the security feature of the EE1DIV registers.
When EE1DIV security feature is enabled, the state of the registers
EE1DIVH and EE1DIVL are locked (including EEDIVSECD bit). The
EE1DIVHNVR and EE1DIVLNVR non-volatile memory registers are
also protected from being erased/programmed.
These prescaler bits store the value of EE1DIV 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-1 related internal timer and circuits. EEDIV[10:0] bits are
readable at any time. They are writable when EELAT = 0 and
EEDIVSECD = 1.
EE1DIV= INT[Reference Frequency(Hz) x 35 x10
1 = EE1DIV security feature disabled
0 = EE1DIV security feature enabled
EEPROM-1 Memory
EEPROM-1 Register Descriptions
-6
EEPROM-1 Memory
+0.5]
Technical Data
105