S9S08SG16E1CTJ Freescale, S9S08SG16E1CTJ Datasheet - Page 54

• Manufacturer Part Number: S9S08SG16E1CTJ
• Manufacturer: Freescale

Specifications of S9S08SG16E1CTJ

• Cpu Family: HCS08
• Device Core Size: 8b
• Frequency (max): 40MHz
• Interface Type: SCI/SPI
• Total Internal Ram Size: 1KB
• # I/os (max): 16
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 12-chx10-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 20
• Package Type: TSSOP
• Program Memory Type: Flash
• Program Memory Size: 16KB
• Lead Free Status / RoHS Status: Compliant

Chapter 4 Memory
memory. In addition to programming the FPS bits to the appropriate value, FPDIS (bit 0 of NVPROT) must
be programmed to logic 0 to enable block protection. Therefore the value 0xF8 must be programmed into
NVPROT to protect addresses 0xFA00 through 0xFFFF.
One use for block protection is to block protect an area of FLASH memory for a bootloader program. This
bootloader program then can be used to erase the rest of the FLASH memory and reprogram it. Because
the bootloader is protected, it remains intact even if MCU power is lost in the middle of an erase and
reprogram operation.
4.5.7
Whenever any block protection is enabled, the reset and interrupt vectors will be protected. Vector
redirection allows users to modify interrupt vector information without unprotecting bootloader and reset
vector space. Vector redirection is enabled by programming the FNORED bit in the NVOPT register
located at address 0xFFBF to zero. For redirection to occur, at least some portion but not all of the FLASH
memory must be block protected by programming the NVPROT register located at address 0xFFBD. All
of the interrupt vectors (memory locations 0xFFC0–0xFFFD) are redirected, though the reset vector
(0xFFFE:FFFF) is not.
For example, if 512 bytes of FLASH are protected, the protected address region is from 0xFE00 through
0xFFFF. The interrupt vectors (0xFFC0–0xFFFD) are redirected to the locations 0xFDC0–0xFDFD. Now,
if an SPI interrupt is taken for instance, the values in the locations 0xFDE0:FDE1 are used for the vector
instead of the values in the locations 0xFFE0:FFE1. This allows the user to reprogram the unprotected
portion of the FLASH with new program code including new interrupt vector values while leaving the
protected area, which includes the default vector locations, unchanged.
4.6
The MC9S08SG32 Series includes circuitry to prevent unauthorized access to the contents of FLASH and
RAM memory. When security is engaged, FLASH and RAM are considered secure resources. Direct-page
registers, high-page registers, and the background debug controller are considered unsecured resources.
Programs executing within secure memory have normal access to any MCU memory locations and
resources. Attempts to access a secure memory location with a program executing from an unsecured
memory space or through the background debug interface are blocked (writes are ignored and reads return
all 0s).
Security is engaged or disengaged based on the state of two nonvolatile register bits (SEC01:SEC00) in
the FOPT register. During reset, the contents of the nonvolatile location NVOPT are copied from FLASH
into the working FOPT register in high-page register space. A user engages security by programming the
NVOPT location which can be done at the same time the FLASH memory is programmed. The 1:0 state
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Security
Vector Redirection
FPS7 FPS6 FPS5 FPS4 FPS3 FPS2 FPS1
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Figure 4-4. Block Protection Mechanism
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MC9S08SG32 Data Sheet, Rev. 8
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