STLED316SMTR STMicroelectronics, STLED316SMTR Datasheet - Page 18

• Manufacturer Part Number: STLED316SMTR
• Description: IC LED CTLR SERIAL 6DIGIT SO-24
• Manufacturer: STMicroelectronics

Specifications of STLED316SMTR

• Applications: LED Controller with Keyscan, 6-Digit
• Interface: Serial
• Voltage - Supply: 4.5 V ~ 5.5 V
• Package / Case: 24-SOIC (7.5mm Width)
• Mounting Type: Surface Mount
• Number Of Digits: 6
• Number Of Segments: 48
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Supply Current: 15000 uA
• Maximum Power Dissipation: 1200 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• For Use With: 497-8417 - BOARD DEMO FRONT PANEL STLED316S497-8399 - BOARD EVAL ST7LITE49M/STLED316S497-8432 - BOARD LED CTLR/DVR STLED316S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6925-2; STLED316SMTR

Key matrix and key-input data storage ram
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Key matrix and key-input data storage ram
During the key scan cycle all the grids are turned off. The first segments turn on is 64 µs.
The key1 and key2 signals will be sampled after 60 µs. The two signals latch into the
internal key buffer. The same applies for other segments.
This key buffer compares the data with the previous key status. If any changes are seen in
the buffer values, then the IRQ_N is asserted. The IRQ_N signal is active low (level). This
IRQ_N signal will be cleared at the end of reading the key buffer (end of byte transfer). The
key buffer must be completely read before the IRQ_N is cleared.
The key matrix is of 8 x 2 configuration, as shown below:
Figure 4.
The data of each key are stored as illustrated below, and are read by the appropriate read
command, starting from the least significant bit.
1
2
The initial key buffer value is “00”. During operation, the buffer values will change depending
upon the values of the key-press.
st
nd
SEG1/KS1
SEG1/KS1
KEY1
KEY2
byte
LSB
LSB
byte
Key matrix
SEG2/KS2
SEG2/KS2
KEY1
KEY2
SEG3/KS3
SEG3/KS3
KEY1
KEY2
SEG4/KS4
SEG4/KS4
KEY1
KEY2
SEG5/KS5
SEG5/KS5
KEY1
KEY2
SEG6/KS6
SEG6/KS6
KEY1
KEY2
SEG7/KS7
SEG7/KS7
KEY1
KEY2
STLED316S
SEG8/KS8
SEG8/KS8
KEY1
KEY2
MSB
MSB