Industrial Electronic Engineers, Inc.
SIZE
A
CODE IDENT NO.
05464
S03805–21–0100
Van Nuys, California
Scale: NONE
Rev C
Sheet 7
2.2.4
Address Counter (AC)
The AC determines the address of the DD RAM or CG RAM in which new data is stored. After writing into (or
reading from) the DD RAM or CG RAM, the AC is incremented or decremented as defined by the
Increment/Decrement bit (Refer to Entry Mode Set instruction).
2.2.5
Display Data RAM (DD RAM)
The DD RAM contains 80 X 8 bits and represents 80 characters. The relationship between the DD RAM
address and position of the characters in the display can be controlled by the user (Refer to Entry Mode Set and
Cursor or Display Shift instructions).
2.2.6
Character Generator ROM (CG ROM)
The CG ROM generates character patterns of 5 X 7 dots from 8 bit character codes. The 192 5 X 7 dot matrix
characters are illustrated in Figure 3.
Figure 3
Correspondence Between Character Codes and Character Patterns
Note
: Addresses 00h through 0Fh are reserved for CG RAM Addressing. Addresses 10h through 1Fh and
80h through 9Fh are not used.
