EF9345 Datasheet, PDF (13/38 Pages) STMicroelectronics – HMOS2 SINGLE CHIP SEMI-GRAPHIC DISPLAY PROCESSOR

EF9345
Table 2
X and Y
Condition
Physical Address AM(3:10)
10
9
8
7
6
5
4
3
Y≥8
X5 = 0
X5 = 1
b0
Y4
Y3
Y2
Y1
Y0
X4
X3
b0
0
0
Y2
Y1
Y0
Y4
Y3
Y0 = 0
b0
0
0
X5
X4
X3
0
0
Y<8
b0 = 0 X3
0
0
I
X5
X4
0
0
Y0 = 1
b0 = 1
I
0
0
I
X5
X4
0
0
SCREEN FORMAT AND ATTRIBUTES
The screen format and attributes are programmed
through 5 indirectly accessible registers : ROR,
TGS, PAT, MAT and DOR. IND command allows
accessing these registers. TGS is also used to
select the timing generator options (see Table 3).
Row and Character Code Format
PAT₇ ; TGS_(6:7)
Two row formats and 5 character code formats are
available but cannot be mixed in a given screen.
DOR register interpretation is completely row for-
mat dependentand is discussed in the correspond-
nig 40 char/row and 80 char/row section.
Screen Partition - Page Pointer ROR
(See Table 3)
The screen is partitioned into 3 areas :
- The margin,
- The service row,
- The bulk of remaining rows.
MAT_(0:3) declares the color of the margin and the
value I_M of its insert attribute.
ROR register points to the page to be displayed and
gives the 3 MSB’s of the Z address : Z₀ = 0
implicitly ; the page block address must be even.
YOR gives the first row buffers to be displayed at
the top of the bulk area. The next row buffers to be
displayed are fetched sequentiallyby incrementing
the Y address (modulo 24). This address never
gets out of the origin block. Incrementation of YOR
by the microprocessor yields a roll up.
Service Row : TGS5 - PAT0
The service row is displayed for 10 TV lines on top
of the screen and does not roll. Following TGS₅, it
is fetched from the origin block at either Y = 0 or Y
= 1. The Y = 1 is a partial row buffer. It can be used
only with variable 40 char./row and an 8 byte
attribute file. The service row may be disabled by
PAT0 = 0 ; it is the displayed as a margin extension.
BULK : TGS0 ; PAT(1:2) ; MAT7
It is displayed after the service row for 200 or 240
TV lines according to TGS₀. Each row buffer is
usually displayed for 10 TV lines. However,
MAT₇ = 1 doubles this figure. Then every character
appears in double height (double height characters
are quadrupled).
PAT1 = 0 and/or PAT2 = 0 disables respectively the
upper 120 lines and/or the lower 80/120 lines of the
bulk.
When disabled, the corresponding TV lines are
displayed as a margin extension.
Cursor MAT(4:6)
To be displayed with the cursor attributes, a char-
acter must be pointed by the main pointer (R6, R7)
and MAT6 must be set. The cursor attributes are
given by MAT(4:5) :
- Complementation : the R, G and B of each pixel
is logically negated.
R, G, B → R, G, B
- Underline : the underline attribute of this charac-
ter is negated.
- Flash : the character is periodically displayed
with, then without, its cursor attributes (50% /
50% ; ≈1Hz).
Flash Enable (PAT6) - Conceal Enable (PAT3)
Any character flashing attribute is a ”don’t care”
when PAT6 = 0. When PAT6=1, a character flashes
if its flashing attribute is set. It is then periodically
displayed as a space (50% / 50% ; 0.5Hz).
PAT3 is a ”don’t care” for 80 char./row formats.
When any 40 char./row format is in use :
- If PAT3 = 0 the conceal attribute of any character
is a don’t care
- If PAT₃ = 1, the conceal attribute of each charac-
ter is interpreted : a concealed character appears
as a space on the screen.
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