STFPC320 STMicroelectronics, STFPC320 Datasheet - Page 40

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

Key matrix
8.1
Description:
Note:
40/75
Key read sequence
Upon a key-press, the IRQ_N/SQW pin will be asserted. The interrupt flag should be read to
know the source of interrupt. The interrupt flag is read by sending the 0x63 command. As
soon as the interrupt buffer is read, the IRQ_N/SQW pin will be de-asserted.
Data Setting Command
Key Data Byte 1
Key Data Byte 2
Key Data Byte 3
For example when the key corresponding to the KEY1/KS1 is pressed, the bit b0 of
Byte 3 will be set. This is decoded as the key value connected to KEY1/KS1 which
could be “PLAY” (for example). When the processor decodes the key value
corresponding to the “PLAY” key, it takes the necessary action (e.g. play the disc).
MSB
MSB
MSB
MSB
b7
b7
b7
0
b6
b6
b6
1
b5
b5
b5
1
b4
b4
b4
0
b3
b3
b3
0
b2
b2
b2
0
b1
b1
b1
0
STFPC320
LSB
LSB
LSB
LSB
b0
b0
b0
0