MAX6850 MAXIM [Maxim Integrated Products], MAX6850 Datasheet - Page 10

• Manufacturer Part Number: MAX6850
• Description: 4-Wire Interfaced, 7-, 14-, and 16-Segment Alphanumeric Vacuum-Fluorescent Display Controller
• Manufacturer: MAXIM [Maxim Integrated Products]

The font comprises 104 characters in ROM, and 24
user-definable characters. The selection from the total
of 128 characters is represented by the lower 7 bits of
the 8-bit digit registers. The MSB, shown as X in the
ROM maps (Tables 7 and 8), controls the DP segment
of the digit; it is set to light the DP.
There are two font maps stored in the MAX6850. One
font map covers 14-segment displays (Table 8), and
the other suits 16-segment displays (Table 7). The F bit
in the configuration register (Table 20) selects between
the two font maps. The F bit may be set either high or
low for 7-segment displays; 7-segment displays use a
subset of the 14- or 16-segment display described in
two font maps (Figure 7).
4-Wire Interfaced, 7-, 14-, and 16-Segment Alpha-
numeric Vacuum-Fluorescent Display Controller
Table 3. Initial Power-Up Register Status
10
VFBLANK polarity
Intensity
Grids
Configuration
User-defined font
address pointer
User-defined fonts
Output map pointer
Output map data
Display test
PUMP
Filament duty cycle
PHASE1
PHASE2
PORT0
PORT1
Shift limit
Cursor
Character and
annunciator data
Character and
annunciator data
______________________________________________________________________________________
REGISTER
UP TO
Character Generator Font Mapping
VFBLANK is high to disable the
display
1/16 (min on)
Display has 1 grid
Shutdown enabled,
configuration unlocked
Address 0x80; pointing to the
first user-defined font location
Predefined for hex fonts
Address 0x80; pointing to the
first entry address
Predefined for 40-digit display
Normal operation
General-purpose output, logic
Minimum duty cycle
General-purpose output, logic
General-purpose output, logic
General-purpose output, logic
General-purpose output, logic
1 output bit
Off
Clear
Clear
POWER-UP CONDITION
—
COMMAND
ADDRESS
UP TO
0x0C
0x0D
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0E
0x0F
0x20
0x7F
—
—
Figure 7. 14- and 16-Segment Fonts Map a Subset of Their 14
or 16 Segments to a 7-Segment Digit
D7
—
X
X
X
1
1
1
X
0
0
0
0
0
0
X
0
0
0
e
7 SEGMENT
f
D6
—
a
g
d
X
X
X
0
0
0
X
0
0
0
0
0
0
0
1
0
0
See Table 11 for power-up patterns.
See Table 32 for power-up patterns.
b
c
dp
D5
—
X
X
X
0
0
0
0
0
0
0
0
0
0
0
1
0
0
REGISTER DATA
MAPS TO
D4
—
X
X
0
0
0
0
X
0
0
0
0
0
0
0
0
0
0
D3
—
X
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
14/16 SEGMENT
e
f
D2
—
X
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
d/d2
a/a1
g1
b
c
D1
—
0
0
0
0
0
0
X
0
0
0
0
0
0
0
0
0
0
dp
D0
—
0
0
0
0
0
0
0
0
1
0
0
0
1
1
0
0
0