ICM7218
11
FN3159.4
May 17, 2016
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Application Examples
8-Digit Microprocessor Display Application
Figure 9 shows a display interface using the lCM7218A/B with
an 8048 family microcontroller. The 8 bit data bus
(DB0/DB7-lD0/ID7) transfers control and data information to the
ICM7218 display interface on successive WRITE
pulses. The
MODE input to the 7218 is connected to one of the I/O port pins
on the microcontroller. When MODE is high, a control word is
transferred. When MODE is low, data is transtered. Sequential
locations in the 8-byte static memory are automatically loaded
on each successive WRITE
pulse. After eight WRITE pulses have
occurred, further pulses are ignored until a new control word is
transferred (See Figure 5 on page 8
). This also allows writing to
other peripheral devices without disturbing the lCM7218A/B.
16-Digit Microprocessor Display
In this application (see Figure 10 on page 12), both lCM7218s
are addressed simultaneously with a 3 bit word, DA2-DA0.
Display data from the 8048 I/O bus (DB7-D80) is transferred to
both lCM7218s simultaneously.
The display digits from both lCM7218s are interleaved to allow
adjacent pairs of digits to be loaded simultaneously from a single
8 bit data bus.
Decimal point information is supplied to the ICM7218s from the
processor on port lines P26 and P27.
No Decode Application
The lCM7218 can also be used as a microprocessor based LED
status panel driver. The microprocessor selected control word
must include "No Decode" and "Data Coming". The processor
writes "Ones" and "Zeroes" into the lCM7218 which in turn
directly drives appropriate discrete LEDs. LED indicators can be
red or green (8 segments x 8 digits = 64 dots/2 per red or green
= 32 channels).
FIGURE 9. 8-DIGIT MICROPROCESSOR DISPLAY
