8-Character, Microprocessor-Compatible, LED Display Decoder Driver
The ICM7244 is an 8-character, alphanumeric display driver
and controller which provides all the circuitry required to
interface a microprocessor or digital system to a 16-segment
display with internal pull-up resistors. It is primarily intended
for use in microprocessor systems, where it minimizes
hardware and software overhead. Incorporated on-chip are a
64-character ASClI decoder, 8 x 6 memory, high power
character and segment drivers, and the multiplex scan
circuitry.
6-bit ASCll data to be displayed is written into the memory
directly from the microprocessor data bus. Data location
depends upon the selection of either Sequential
(MODE = 1) or Random access mode (MODE = 0). In the
Sequential Access mode the first entry is stored in the
lowest location and displayed in the “left-most” character
position. Each subsequent entry is automatically stored in
the next higher location and displayed to the immediate
“right” of the previous entry. A DISPlay FULL signal is
provided after 8 entries; this signal can be used for
cascading devices together. A CLeaR pin is provided to
clear the memory and reset the location counter. The
Random Access mode allows the processor to select the
memory address and display digit for each input word.
The character multiplex scan runs whenever data is not
being entered. It scans the memory and CHARacter drivers,
and ensures that the decoding from memory to display is
done in the proper sequence. Intercharacter blanking is
provided to avoid display ghosting.