7. Vacuum Fluorescent Display (VFD) Controller/Driver
The H8/3714 Series, the H8/3724 Series and H8/3754 Series include a vacuum fluorescent
display (VFD) controller/driver and high breakdown voltage high current pins. These allow the
H8/3714 Series, the H8/3724 Series and H8/3754 Series to directly drive vacuum fluorescent
displays.
Features: • Up to 28 segment pins and up to 16 digit pins (of which 8 are shared function
pins) built in.
• The VFD brightness can be adjusted over eight levels using the dimmer
function.
• The display digit can be changed automatically.
• The digit and segment pins can be switched to function as general purpose high
breakdown voltage pins.
• A key scan period can be enabled or disabled.
• Generates an interrupt at the start of the key scan period.
Block Diagram
IRRKS
<Notation>
VFDR:
VFD digit control register
DBR:
Digit beginning register
VFSR:
VFD segment control register
IRRKS:
Key scan interrupt request flag
VFDR
Display timing
generator
Digit pins
Internal data bus
DBR
105
Peripheral Functions
VFSR
VFD display RAM
Segment pins