STV7710WAF Ver la hoja de datos (PDF) - STMicroelectronics
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STV7710WAF Datasheet PDF : 19 Pages
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CIRCUIT DESCRIPTION
STV7710/WAF
4.3 Description
STV7710/WAF includes all the logic and power circuits necessary to drive electrodes of a vacuum
fluorescent display (VFD). Binary values of each pixel of the displayed line are loaded into the shift
register DATA_A/B data bus. Data is shifted at each low to high transition of the CLK clock. After 96
shifts, the data is available at the output of the shift register. This output can be used to cascade
several Ics to drive higher resolution displays.
The forward /reverse (F/R) input is used to select the direction of the shift register. Data input/output
status is set according to the selected direction (refer to Table 6).
The maximum frequency of the shift clock is 40MHz.
When the STB signal is high, data are transferred from the shift register to the latch and power
output stages.
All the output data are kept memorized and held in the latch stage when the latch input STB is set
at low level.
Vsssub and Vsslog must be connected as close as possible to the logical reference ground of the
application. Also, make sure that TEST input pin is connected to ground (Figure 8).
STV7710/WAF is supplied with a 5 volt power supply. All the logic inputs can be driven either by 5V
CMOS logic, or by 3.3V CMOS logic.
Table 7: Shift register truth table
Input
F/R
CLK
H
↑
H
H or L
L
↑
L
H or L
Data-in / Data-out
DATA_A
Data-in
-
Data-out
-
DATA_B
Data-out
-
Data-in
-
Shift register function
Forward shift
Steady
Reverse shift
Steady
TEST Qn
L
X
L
X
L
X
L
L
L
H
Table 8: Power output truth table
STB
X
X
L
H
H
BLK
H
L
L
L
L
POC
X
L
H
H
H
Driver Output
all “Low”
all “High”
Qn
L
H
Comments
Output at low level
Output at high level
Data latched
Data transfered
Data transfered
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