HT16565_12 Datasheet, PDF (1/9 Pages) Holtek Semiconductor Inc – 24 Hour System VFD Digital Clock

HT16565
24 Hour System VFD Digital Clock
Features
· VFD display 24 hour clock function
· 4.194304MHz crystal oscillation
· Zero adjust function
· Integrated voltage regulator permits wide 4V to 18V
operating voltage range
· Four level contrast control function
· 44-pin QFP package
General Description
The HT16565 provides direct drive to VFD panels to im-
plement a 24 hour clock function. In addition to obtaining
its time base from a 4.194304MHz crystal oscillation
source and in having a wide operating voltage, the de-
vice also contains a host of other features. These in-
clude a choice of adjustment modes, including single
push increment or 2Hz fast forward functions. Additional
features are provided in the form of Zero adjustment and
four levels of contrast control.
Block Diagram
O SCO
O SCI
O s c illa to r
V DD
F r e q u e n c y D iv id e r s 1 H z
CM OS
64H z
1H z
TEST3
TEST2
TEST1
A /C
SE
ZA
MS
HS
T est
A d ju s tm e n t
V DD V DD
S e c o n d C o u n te r
a1
b1
c1
M in u te C o u n te r
D ecoder
S egm ent
H o u r C o u n te r
D ecoder
S egm ent
C O N T2
C O N T1
D IM
V DD
C o n tra s t
A d ju s tm e n t
g3
b4
c4
a4,d4
e4,g4
TEST4
S 1224
V DD
V DD
Rev. 1.10
1
May 24, 2012