
4. DISPLAYCONTROL
4.1 SCREENDESCRIPTION
A screen is composed of successive scan lines
gathered in one or several strips. Each strip is
defined by a descriptor stored in memory. A list of
descriptors allows screen composition, different
screenscanbedefinedin memory(see application
note and Figures 13, 14.).
Two kinds of strip are available:
-
Uniform color strip
Applications:
- vertical front and back porch
- vertical synchro
- borderlines
Parameters:
- number of scan lines
- color
-
Characterstrip
Characters and attributes are defined by a suc-
cessionof codesstored inmemory; thanksto the
character code,a memoryaddress is calculated
and used to get the characterpattern.
Parameters:
- address of the first code
- size,display enable
* U0 is uniformstrip number0, R0 is character strip number 0
DESCRIPTORLIST
CONTENTS
SCAN LINES
SUM
VERT REGISTER
COMMENTS
VERT REGISTER
COMMENTS
242 Scan Lines(00F0h)
312 Scan Lines (0136h)
U2 Strip is cut (red uniform strip)
U2 (red), U3 (yellow), U4 (cyan) and part of U5 (white) uniform strip are displayed
1460
A8AA
0A02
F8AA
20AB
48AB
D0BA 1402
1906
1903
1907
U0*
U1
R0*
R1
R2
R18
R19
U2
U3
U4
U5
10
10
20
25
25
25
220
230
250
275
300
325
20
10
10
10
10
20
30
40
50
60
9
Figure13 :
Programmation of Number of Scan Lines - VerticalRegister VERT (2FF0/2FF1)
and Descriptor List
OTHER
25th ROW CODES
OTHER
1st ROW CODES
3rd ROW CODES
2nd ROW CODES
OTHER
23th ROW CODES
OTHER
RAM
PAGE CODES LOCATION
UNIF 0
ROW 0
ROW 1
ROW 2
ROW 22
ROW 2
ROW 24
UNIF 1
TOP UNIFORM STRIP
BOTTOMUNIFORM STRIP
1st CHARACTER ROW
2nd CHARACTERROW
3rd CHARACTER ROW
23th CHARACTERROW
24th CHARACTER ROW *
25th CHARACTERROW
Address
of the list
ADDR
REGISTER
RAM
DESCRIPTOR LIST
SCREEN
* Identical to row 2
9
Figure14 :
Relation betweenScreen Location/DescriptorPointer/RAMPage Codes
STV9410
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