EF9345 Datasheet, PDF (23/38 Pages) STMicroelectronics – HMOS2 SINGLE CHIP SEMI-GRAPHIC DISPLAY PROCESSOR

EF9345
The cells of one given character set should be layed
in one block.
Up to 100 character cells may be addressed in
each set (or 200 for low resolution quadrichrome
only). The location in memory, where to fetch the
sets in use, are declared by DOR register (Fig-
ure 22). For each type of set, it gives the MSB(s)
of the Z block address. EF9345 reads the Z LSB(s)
in the B byte of the (equivalent) long code. As usual,
the character code is read in the C byte. NT is
derived from the TV line rank in the row and the
double height status.
Loading User Defined Character Set
Before loading a character set into RAM, the user
must :
- Assign a name to the set :
• G’0, G’10 or G’11 for bichrome characters.
• From Q₀ to Q₇ for quadrichrome charac-
ters.
Figure 22 : UDS Fetch to Display
- Assign a character number to each character
belonging to this set, character numbers range
from 0 to 3 and 32 to 127.
• It is binary coded into 7 bits C(0:6) - C(0:6)
will be loaded later on into a C byte charac-
ter code in order to display the character.
- A pointer to a character slice in memory is then
manufactured from :
• The character number C(0:6)
• The slice number NT(0:3)
• The block number assigned to the set
Z(0:3)
Figure 23 shows how to proceed with the auxiliary
pointer and the OCT command.
Note : The main pointer may be also used. When
sequentially accessing slices of a given
character, auto incrementation is helpless.
~ ^MEMORY ~
DOR G’₀ (alpha UDS)
1 Kbyte
2 Kbytes
G’₀
~
~
76543210
DOR G’₁
(semi-grap hic UDS)
Z₃ Z₃ Z₂ Z₁ Z₃ Z₂ Z₁ Z₀ DOR register
G’₁₀
Even block
DOR Q DOR G’₁
DOR G’₀
G’₁₁
Odd block
~
~
Q₀
DOR Q
(quadrichr ome)
76543210
1
X
X
X
X
X
X
X
CHARACTER LONG
CODE B BYTE
8 Kbytes
Q₁
~
~
Q₇
~
~
UDS Set
#
B7 B6 B5 Z₃
G’₀
1 0 0 DOR₃
G’₁₁
1 0 1 DOR₆
Q0 - Q7 1 1 X DOR₇
Z Address
Z₂
DOR₂
DOR₅
B5
Z₁
DOR₁
DOR₄
B3
Z₀
DOR₀
B4
B4
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