STFPC320 STMicroelectronics, STFPC320 Datasheet - Page 69

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

STFPC320
17.7
Note:
Timing characteristics
V
Figure 30. Key scanning and display timing
Pulse width of segment signal is decided by oscillator frequency. The value can be modified
by trimming R
matrices are stored in RAM.
The key scan is only at the end of the frame when the display is ON. When the display is
OFF, the key scan takes place continuously. The grid is turned off during the key scan.
DD
SEG Output
= 3.3V, T
G1
G2
G3
Gn
t
DISP
A
OSC
1/16 t
= -20 to 70°C, unless otherwise noted. Typical values are at T
DIG1
≈ 500µs
. One cycle of key scanning consists of one frame and data of 12 x 2
DISP
(1)
DIG2
DIG3
1 frame = t
DISP
x (n+1)
DIGn
Electrical characteristics
Key scan data
A
= 25°C
DIG1
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