STFPC320 STMicroelectronics, STFPC320 Datasheet - Page 41

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

STFPC320
9
9.1
LED port
Data is written to the LED port by a write command, starting from the most significant bit of
the port. When a bit of this port is set to 0, the corresponding LED lights up; when the bit is
set to a 1, the LED turns off. The data of bits 5 through 8 are ignored. Upon first power-up,
all the LEDs are turned OFF.
Writing to LED sequence
Data (will turn on all the 4 the LEDs)
For example, the LEDs can be connected to indicate ‘Power-On’, ‘Standby’, ‘Record’,
‘Function’ status on front panel. If the data bit corresponding to the LED is a ‘0’, the LED will
turn-on during normal operation and standby mode.
So as an example, to turn on the LED for standby indication, the processor must write ‘0’ to
the corresponding data bit before de-asserting the READY pin (i.e. before going into STBY).
This will continuously keep the STBY LED ‘ON’ during standby mode of operation.
Data Setting Command
Data Byte
MSB
MSB
-
-
-
-
MSB
MSB
X
0
-
-
-
-
X
1
b3
b3
X
0
b2
b2
b1
b1
X
0
LSB
LSB
b0
b0
0
0
0
0
Don’t Care
Don’t Care
LED1
LED1
LED2
LED2
LED3
LED3
LED4
LED4
1
0
LED port
LSB
LSB
1
0
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