ICM7218_15 Datasheet, PDF (9/11 Pages) Intersil Corporation – 8-Digit LED Microprocessor-Compatible Multiplexed Display Decoder Driver

ICM7218
FIGURE 9. 8-DIGIT MICROPROCESSOR DISPLAY
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 7218 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). This also allows writing to other peripheral devices
without disturbing the lCM7218A/B.
16-Digit Microprocessor Display
In this application (see Figure 10), 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).
9
FN3159.3
September 15, 2015