Manualshelf

Velleman 4-Digit Display Datasheet-2

ManualsBrandsWhadda ManualsLCD & Display4-Digit Display
12345678910
LED Drive Control Special Circuit TM1637
2
©Titan Micro Electronics www.titanmec.com
V2.4
Pin functions
Symbols
Pin name
Pin
No.
Description
DIO
Data
input/output
17
It is used for serial data input and output. The input data has a
low level fluctuation while high level transfer at SCLK. Once
one bit is transferred, one ACK is generated at failing edge of
the 8
th
clock inside the chip.
CLK
Clock input
18
It is used for data input and output at rising edge.
K1~K2
Data input by
keyboard scan
19-20
Inputting the pin data here and it will be latched when the
display cycle is over.
SG1~SG8
Output
(segment)
2-9
Segment Output (also keyboard scan) and N-channel open
drain output
GRID6~GRID1
Output (bit)
10-15
Bit output and P-channel open drain output
VDD
Logic Supply
16
Anode power connection
GND
logic ground
1
Grounding connection
Electrostatic discharge led by much static at dry weather or environment could damage the integrated circuit. TITAN MICRO
ELECTRONICS suggests you to take every measure to protect integrated circuit. ESD damage or decreased performance by
inappropriate operation or welding could lead to chip failure.
Read the key scan data
Key scan matrix of 8×2bit is shown as the following:
S1
S5 S9 S13
S2
S6 S10 S14
S3
S7 S11 S15
S4
S8 S12 S16
K1
K2
SG1
SG2
SG3
SG4
SG5
SG6
SG7
SG8
When a key is pressed, the key scan data is as follows: (Where low level is forward and high level is backward,
1110_1111 stands for 0xF7) .
SG1
SG3
SG4
SG5
SG7
SG8
K1
1110_1111
1010_1111
0010_1111
1100_1111
1000_1111
0000_1111
K2
1111_0111
1011_0111
0011_0111
1101_0111
1001_0111
0001_0111
Note: Where there is no key pressed down, the key read data should be 1111_1111 with forward low level and backward high level. Since
strong interference exists in the use of kitchen appliances, such as induction cooker, negative edge trigger mode was applied in TM1637 to
avoid mistake trigger, which is also the called “key jumping”. TM 1637 doesn’t support combined key pressing.