ST10F271Z1T3 STMicroelectronics, ST10F271Z1T3 Datasheet - Page 38

• Manufacturer Part Number: ST10F271Z1T3
• Description: MCU 16BIT 128KBIT FLASH 144-TQFP
• Manufacturer: STMicroelectronics
• Series: ST10r

Specifications of ST10F271Z1T3

• Core Processor: ST10
• Core Size: 16-Bit
• Speed: 40MHz
• Connectivity: CAN, I²C, SSC, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 111
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 12K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 24x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 144-TQFP, 144-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

Internal Flash memory
5.5.8
5.5.9
5.6
38/185
Figure 6.
When the Access Protection is enabled, Flash registers can not be written, so no
program/erase operation can be run on I-Flash. To enable the access to registers again, the
Temporary Access Unprotection procedure has to be followed (see
Write protection
The Flash modules have one level of write protections: each sector of each bank of each
Flash module can be software write protected by programming at 0 the related bit W0Px in
FNVWPIRL register.
Temporary unprotection
Bits W0Px of FNVWPIRL can be temporary unprotected by executing the set protection
operation and by writing 1 into these bits.
To restore the write protection bits it is necessary to reset the microcontroller or to execute a
set protection operation and write 0 into the desired bits.
In reality, when a temporary write unprotection operation is executed, the corresponding
volatile register is written to 1, while the non-volatile registers bits previously written to 0 (for
a protection set operation), will continue to maintain the 0. For this reason, the user software
must be in charge to track the current write protection status (for instance using a specific
RAM area), it is not possible to deduce it by reading the non-volatile register content (a
temporary unprotection cannot be detected).
To temporary unprotect the Flash when the access protection is active, it is necessary to set
at 1 the bit TAUB in XFVTAUR0. This bit can be write at 1, only executing from Flash: in this
way only an instruction executed from Flash can unprotect the Flash itself.
To restore the access protection, it is necessary to reset the microcontroller or to write at 0
the bit TAUB in XFVTAUR0.
Write operation examples
In the following, examples for each kind of Flash write operation are presented.
Fetching from IFlash
Fetching from IRAM
Fetching from XRAM
Fetching from external
memory
Summary of access protection level
jump to IFlash
Read IFlash /
Yes / Yes
No / Yes
No / Yes
No / Yes
XRAM or ext mem
ext mem / jump to
Read XRAMS or
Yes / Yes
Yes / Yes
Yes / Yes
Yes / Yes
Read Flash
registers
Yes
Yes
Yes
Yes
Section
5.5.9).
Write Flash
ST10F271Z1
registers
No
No
No
No