Reset; Table 9. Reset Jumper; Figure 9. Power Supply Jumpers Location - STMicroelectronics MB467 User Manual

UM0178
Figure 9.
J23-25
J22
J27
J29
J26
J28
J35
J30
J34
J37
J38
J39
J42
4.9

Reset

Power on reset is driven by the L4998 Safety Power Regulator (SPR). The SPR provides an
output (RST) to indicate the regulation status of VCC. The RST output is asserted low
whenever VCC falls below its low voltage threshold or VCC rises above its over-voltage
threshold.
The RST signal is connected to the RESETB pin of the two safing ASIC's and to the RESETIN
pin of the CPU Board Connector. When this signal is asserted low, all components in the board
and any connected microcontroller board will be reset.
Please, note that during a deployment, the L9658/L9654 ignores but latches internally the reset
signal. Only after the deployment is complete, the reset signal is asserted, any output operation
interrupted and the ASIC internal registers reset to their default state.
RESETB signal of the two ASIC can be forced high (pull up), regardless of the RST signal
coming from the SPR, through jumper J36.
Table 9.
Name
J36
Power supply jumpers location
Reset jumper
Figure
Figure 10
Description
Force pull up of the RESETB signal
4 Hardware
J51
J40
J45
J46
J48-50
J31-33
J41
J43
J44
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