STR712FR1 STMicroelectronics, STR712FR1 Datasheet - Page 47

• Manufacturer Part Number: STR712FR1
• Description: ARM7TDMI™ 16/32-BIT MCU WITH FLASH, USB, CAN, 5 TIMERS, ADC, 10 COMMUNICATIONS INTERFACES
• Manufacturer: STMicroelectronics

Specifications of STR712FR1

• 5 Power Saving Modes: SLOW, WAIT, LPWAIT, STOP and STANDBY modes
• Conversion Range: 0 to 2.5 V

STR71xF
4.3.4
EMC characteristics
Susceptibility tests are performed on a sample basis during product characterization.
Functional EMS (electro magnetic susceptibility)
Based on a simple running application on the product (toggling 2 LEDs through I/O ports),
the product is stressed by two electro magnetic events until a failure occurs (indicated by the
LEDs).
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A device reset allows normal operations to be resumed. The test results are given in the
table below based on the EMS levels and classes defined in application note AN1709.
Designing hardened software to avoid noise problems
EMC characterization and optimization are performed at component level with a typical
application environment and simplified MCU software. It should be noted that good EMC
performance is highly dependent on the user application and the software in particular.
Therefore it is recommended that the user applies EMC software optimization and
prequalification tests in relation with the EMC level requested for his application.
Software recommendations:
The software flowchart must include the management of runaway conditions such as:
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Prequalification trials:
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the RESET pin or the Oscillator pins for 1
second.
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behavior is detected, the software can be hardened
to prevent unrecoverable errors occurring (see application note AN1015).
In the case of an ARM7 CPU, in order to write robust code that can withstand all kinds of
stress, such as very strong electromagnetic disturbance, it is mandatory that the Data Abort,
Prefetch Abort and Undefined Instruction exceptions are managed by the application
software. This will prevent the code going into an undefined state or performing any
unexpected operation.
ESD: Electro-Static Discharge (positive and negative) is applied on all pins of the
device until a functional disturbance occurs. This test conforms with the IEC 1000-4-2
standard.
FTB: A Burst of Fast Transient voltage (positive and negative) is applied to V
V
conforms with the IEC 1000-4-4 standard.
Corrupted program counter
Unexpected reset
Critical Data corruption (control registers...)
SS
through a 100pF capacitor, until a functional disturbance occurs. This test
Electrical parameters
DD
and
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