Holtek Semiconductor HT16561
The HT16561 provides direct drive to VFD panels to implement a 12 hour clock function. These include a choice of adjustment modes, including single push increment or 2Hz fast forward functions.FEATURES
● VFD display 12 hour clock function● 4.194304MHz crystal oscillation
● Zero adjust function
● Integrated voltage regulator permits wide 4V to 16V operating voltage range
● Four level contrast control function
● 44-pin QFP package
GENERAL DESCRIPTION
In addition to obtaining its time base from a 4.194304MHz crystal oscillation source and in having a wide operating voltage, the device also contains a host of other features. Additional features are provided in the form of Zero adjustment and four levels of contrast control. Block Diagram C M O S O S C O O s c illa to r O S C I V T E S T 3 T E S T 2 T E S T 1 V D D 6 4 H z F r e q u e n c y D iv id e r s 1 H z 1 H z T e s t A d ju s tm e n t S e c o n d C o u n te r (1 /6 0 ) a 1 D D V D D b 1 M in u te C o u n te r (1 /6 0 ) D e c o d e r S e g m e n t D r iv e r [P C H c 1 T im e A d ju s tm e n t A /C S E Z A M S H S H o u r C o u n te r (1 /1 2 ) D e c o d e r S e g m e n t O p e n D r a in ] A M /P M g 3 b 4 c 4 A M V C O N T 2 C O N T 1 D IM D D C o n tra s t A d ju s tm e n t P M V T E S T 4 D D Rev.