mc33905s Freescale Semiconductor, Inc, mc33905s Datasheet - Page 44

• Manufacturer Part Number: mc33905s
• Description: System Basis Chip Gen2 With High Speed Can And Lin Interface
• Manufacturer: Freescale Semiconductor, Inc

SAFE Mode A Illustration:
SPI configuration.
44
33904/5
FAIL SAFE OPERATION
BEHAVIOR AT POWER UP AND POWER DOWN
The figure below illustrate the event, and consequences when SAFE Mode A is selected via the appropriate debug resistor or
gnd
step 1: Failure illustration
enter in SAFE mode to evaluate resistor at DBG pin
RSTb
SAFE
Vdd
100ms delay time to enter in SAFE mode
RSTb
SAFE
and monitor ECU external events
RSTb
SAFE
Vdd
Vdd
Behavior illustration for safe state A (Rdg <6kOhms), or selection by SPI
8 x 256ms delay time to enter in SAFE mode
100ms deglitcher time to activate SAFE and
failure event, i.e W/D
OFF state ON state
to evaluate resistor at DBG pin
OFF state ON state
OFF state
failure event, Vdd low
failure event, Reset s/c gnd
and monitor ECU external events
and monitor ECU external events
to evaluate resistor at DBG pin
1st
Vdd_UV th
Figure 25. SAFE Mode A Behavior Illustration
2.5V
100ms
2nd
100ms
ON state
8th
gnd
step 2: Consequence on
Vdd, RSTb and SAFE
SAFE
RSTb
Vdd
SAFE
SAFE
RSTb
RSTb
Vdd
Vdd
Vdd < Vdd_UVth
Analog Integrated Circuit Device Data
Freescale Semiconductor