SDA55XX Datasheet, PDF (173/230 Pages) Infineon Technologies AG – Preliminary & Confidential

SDA 55xx
Preliminary & Confidential
Display
18.2
Display Memory
The display memory is located inside the internal XRAM. The start address of
the display memory is at memory address DISPOINT_h. This memory address is
defined by the user due to a pointer. For each character position three bytes in
the display memory are reserved. These three bytes are stored in a serial
incremental order for each character and used to define the display attributes of
each single character position. The complete amount of allocated display
memory depends on the display resolution. In vertical direction the character
display area is fixed to 25 rows. In horizontal direction the character display
area can be adjusted from 33 up to 64 columns.The following figure is an
example for a character display area resolution of 25 rows and 40 columns:
row
No.
address
i = 0d
.....
i =39d
DISPOINT_h
0
+0_h
+ i x 3h
DISPOINT_h
1
+78_h
+ i x 3_h
DISPOINT_h
2
+F0_h
+ i x 3_h
...
...
Character Display Area
DISPOINT_h
23
+AC8_h
+ i x 3_h
DISPOINT_h
24
+B40_h
+i x 3_h
Figure 18 Display Memory Organization of TVTpro
Following formula helps to calculate a memory address of a character position
(X_CH, Y_CH) depending on the count of characters in horizontal direction (defined
in the binary parameters (DISALH4..DISALH0)_h ) and a display start address
DISPOINT_h:
CHARADRESS_h=DISPOINT_h+(Y_CH x ((DISALH4..DISALH0)_h+21_h)+X_CH) x 3_h)
Semiconductor Group
173
User’s Manual July 99