MC9S12XET256CAG Freescale Semiconductor, MC9S12XET256CAG Datasheet - Page 924

• Manufacturer Part Number: MC9S12XET256CAG
• Description: MCU 16BIT 256K FLASH 144-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HCS12r

Specifications of MC9S12XET256CAG

• Core Processor: HCS12X
• Core Size: 16-Bit
• Speed: 50MHz
• Connectivity: CAN, EBI/EMI, I²C, IrDA, SCI, SPI
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 119
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.72 V ~ 5.5 V
• Data Converters: A/D 24x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 144-LQFP
• Processor Series: S12XE
• Core: HCS12
• 3rd Party Development Tools: EWHCS12
• Development Tools By Supplier: KIT33812ECUEVME, EVB9S12XEP100, DEMO9S12XEP100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Chapter 25 256 KByte Flash Module (S12XFTM256K2V1)
25.4
25.4.1
Flash command operations are used to modify Flash memory contents or configure module resources for
EEE operation.
The next sections describe:
25.4.1.1
Prior to issuing any Flash program or erase command after a reset, the user is required to write the
FCLKDIV register to divide OSCCLK down to a target FCLK of 1 MHz.
values for the FDIV field based on OSCCLK frequency.
When the FCLKDIV register is written, the FDIVLD bit is set automatically. If the FDIVLD bit is 0, the
FCLKDIV register has not been written since the last reset. If the FCLKDIV register has not been written,
any Flash program or erase command loaded during a command write sequence will not execute and the
ACCERR bit in the FSTAT register will set.
25.4.1.2
The Memory Controller will launch all valid Flash commands entered using a command write sequence.
Before launching a command, the ACCERR and FPVIOL bits in the FSTAT register must be clear (see
Section
sequence. If CCIF is 0, the previous command write sequence is still active, a new command write
sequence cannot be started, and all writes to the FCCOB register are ignored.
924
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•
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How to write the FCLKDIV register that is used to generate a time base (FCLK) derived from
OSCCLK for Flash program and erase command operations
The command write sequence used to set Flash command parameters and launch execution
Valid Flash commands available for execution
25.3.2.7) and the CCIF flag should be tested to determine the status of the current command write
Functional Description
Flash Command Operations
Writing the FCLKDIV Register
Command Write Sequence
Programming or erasing the Flash memory cannot be performed if the bus
clock runs at less than 1 MHz. Setting FDIV too high can destroy the Flash
memory due to overstress. Setting FDIV too low can result in incomplete
programming or erasure of the Flash memory cells.
Writes to any Flash register must be avoided while a Flash command is
active (CCIF=0) to prevent corruption of Flash register contents and
Memory Controller behavior.
MC9S12XE-Family Reference Manual , Rev. 1.23
CAUTION
NOTE
Table 25-9
shows recommended
Freescale Semiconductor