CD00237391 Datasheet, PDF (93/177 Pages) STMicroelectronics – ARM-based 32-bit MCU, 150DMIPs, up to 1 MB Flash/128+4KB RAM

STM32F20xxx
Electrical characteristics
Table 39. EMS characteristics
Symbol
Parameter
Conditions
Level/
Class
V_FESD
Voltage limits to be applied on any I/O pin to
induce a functional disturbance
V_DD = 3.3 V, LQFP100, T_A = +25 °C,
f_HCLK = 75 MHz, conforms to
IEC 61000-4-2
2B
V_EFTB
Fast transient voltage burst limits to be
applied through 100 pF on V_DD and V_SS
pins to induce a functional disturbance
V_DD = 3.3 V, LQFP100, T_A = +25 °C,
f_HCLK = 75 MHz, conforms to
4A
IEC 61000-4-2
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:
● Corrupted program counter
● Unexpected reset
● Critical Data corruption (control registers...)
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the NRST 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).
Electromagnetic Interference (EMI)
The electromagnetic field emitted by the device are monitored while a simple application,
executing EEMBC^® code, is running. This emission test is compliant with SAE IEC61967-2
standard which specifies the test board and the pin loading.
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