STFPC320 STMicroelectronics, STFPC320 Datasheet - Page 12

• Manufacturer Part Number: STFPC320
• Description: Front Panel Controller/driver With Standby Power Management And Real-time Clock
• Manufacturer: STMicroelectronics

Functional description
4.3
Note:
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2
3
1
Entering standby mode
The STFPC320 will control the power to the main board using the STBY pin. During normal
operation, the STBY pin will be a low level which will externally control a power MOS switch
to enable power to the main board. The STFPC320 will assert the STBY pin to a high when
any one of the following conditions occur:
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●
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Guard timer can be kept on during normal condition when READY is high (depending on the
user).
In this condition, the guard timer can be disabled or enabled. If the guard timer is enabled,
the timer needs to be cleared before the programmed count of the timer is reached. If the
programmed count is reached, the STBY will be asserted.
It is advisable not to enable the guard timer during normal operation.
Figure 5.
Processor fails to respond by enabling the READY pin within 10s upon first power-up
(cold boot up)
Guard timer counts down to 0s
Processor makes the READY pin to low (can happen in various conditions such as user
presses STBY key on Front Panel, STBY key on Remote Control, etc)
Standby mode behaviour
STFPC320