ICM7228_15 Datasheet, PDF (13/19 Pages) Intersil Corporation – 8-Digit, Microprocessor-Compatible, LED Display Decoder Driver

ICM7228
Display Formats
The ICM7228A and ICM7228B have three possible display
formats; Hexadecimal, Code B and No Decode. Table 5
shows the character sets for the decode modes and their
corresponding input code.
The display formats of the ICM7228A/B are selected by
writing data to bits ID4, ID5 and ID6 of the Control Register
(See Table 1 and 2 for input Definitions). Hexadecimal and
Code B data is entered via ID0-lD3 and ID7 controls the
decimal point.
TABLE 5. DISPLAY CHARACTER SETS
INPUT DATA CODE
DISPLAY CHARACTERS
ID3 ID2 ID1 ID0 HEXADECIMAL CODE B
0
0
0
0
0
0
0
0
0
1
1
1
0
0
1
0
2
2
TABLE 5. DISPLAY CHARACTER SETS (Continued)
INPUT DATA CODE
DISPLAY CHARACTERS
ID3 ID2 ID1 ID0 HEXADECIMAL CODE B
0
0
1
1
3
3
0
1
0
0
4
4
0
1
0
1
5
5
0
1
1
0
6
6
0
1
1
1
7
7
1
0
0
0
8
8
1
0
0
1
9
9
1
0
1
0
A
-
1
0
1
1
b
E
1
1
0
0
C
H
1
1
0
1
d
L
1
1
1
0
E
P
1
1
1
1
F
(Blank)
I/O OR
MEMORY
WRITE PULSE
A3 - A15
DATA BUS D0 - D7
5
DECODER
ENABLE
ADDRESS
DECODER
DEVICE SELECT
AND
WRITE PULSE
ID0 - ID3
AND ID7
INTERSIL
ICM7228C
WRITE
SEGMENTS
DRIVE
A0 - A2
DA0 - DA2
DIGITS
DRIVE
ADDRESS BUS A0 - A15
LED DISPLAY
FIGURE 10. ICM7228C MICROPROCESSOR SYSTEM INTERFACING
a
fb
g
ec
d
DP
FIGURE 11. DIGITS SEGMENT ASSIGNMENTS
The No Decode mode of the ICM7228A and ICM7228B
allows the direct segment-by-segment control of all 64
segments driven by the device. In the No Decode mode, the
input data directly control the outputs as shown in Table 6.
TABLE 6. NO DECODE SEGMENT LOCATIONS
DATA
INPUT
ID7
ID6 ID5 ID4 ID3 ID2 ID1 ID0
Controlled Decimal a b c e g f d
Segment
Point
An input high level turns on the respective segment, except
for the decimal point, which is turned on by an input low level
on ID7.
The No Decode mode can be used in different applications
such as bar graph or status panel driving where each
segment controls an individual LED.
The ICM7228C has only the Hexadecimal and Code B
character sets. The HEXA/CODE B/SHUTDOWN input, pin
9, requires a three level input. Pin 9 selects the Hexadecimal
format when pulled high, the Code B format when floating or
driven to mid-supply, and the shutdown mode when pulled
low (See Table 3). Table 5 also applies to the ICM7228C.
Shutdown and Display Banking
When shutdown, the ICM7228 enters a low power standby
mode typically consuming only 1A of supply current for the
ICM7228A/B and 2.5A for the ICM7228C. In this mode the
ICM7228 turns off the multiplex scan oscillator as well as the
digit and segment drivers. However, input data can still be
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