stled325 STMicroelectronics, stled325 Datasheet - Page 42

• Manufacturer Part Number: stled325
• Description: I?c Interfaced, Advanced Led Controller/driver With Keyscan, Standby Power Management And Real Time Clock Rtc
• Manufacturer: STMicroelectronics

KEY matrix and key-input data storage RAM
6
42/62
KEY matrix and key-input data storage RAM
The key matrix is of 8x2 configuration, as shown below:
Figure 15. KEY matrix and key-input data storage RAM
The data of each key are stored as illustrated below, and are read by the appropriate read
command, starting from the least significant bit.
All the front panel keys can be configured as hot keys using the “configuration mode setting
command”. Alternatively, any number of keys out of 16 keys can be programmed for hot key
functions by using the hot-key setting command.
It is recommended to read the hot key values immediately upon STBY de-assertion. If they
are not read within the guard preset timer value, the hot key data are cleared.
It is recommended to have 10 KΩ pull down resistors on the KEY1 and KEY2 input pins and
the output SEG/KS pins can see a maximum load of 300pF. This load condition is important
for the key dis-charge cycle time.
Key 1
Seg1
Seg5
b0
Key 2
KS1
KS5
b1
Key 1
Seg2
Seg6
b2
Doc ID 17576 Rev 1
Key 2
KS2
KS6
b3
Key 1
Seg3
Seg7
b4
Key 2
KS3
KS7
b5
Key 1
Seg4
Seg8
b6
STLED325
Key 2
KS4
KS8
b7