EF9345 Datasheet, PDF (10/38 Pages) STMicroelectronics – HMOS2 SINGLE CHIP SEMI-GRAPHIC DISPLAY PROCESSOR

EF9345
FUNCTIONAL DESCRIPTION
The EF9345 is a low cost, semigraphic, CRT con-
troller.
It is optimized for use with a low cost, monochrome
or color TV type CRT (64ms per line, 50 or 60Hz
refresh frequency).
The EF9345 displays up to 25 rows of 40 charac-
ters or 25 rows of 80 characters.
The on-chip character generator provides a 128
standard, 5 x 7, character set and standard semi-
graphic sets.
More use definable (8 x 10) alphanumeric or semi-
graphic sets may be mapped in the 16 K x 8 private
memory addressing space.
These user definable sets are available only in 40
characters per row format.
Microprocessor Interface
The EF9345 provides an 8-bit, adress/data multi-
plexed microprocessor interface.
It is directly compatible with popular (6801, 8048,
8051, 8035, ...) microprocessors.
Registers
The microprocessor directly accesses 8 registers :
- R0 : Command/status register.
- R1, R2, R3 : Data registers.
- R4, R5, R6, R7 : Each of these register pairs
points into the private memory.
Through these registers, the microprocessor indi-
rectly accesses the private memory and 5 more
registers :
- ROR, DOR : Base address of displayed page
memory and used external character generators.
- PAT, MAT, TGS : Used to select the page attrib-
utes and format, and to program the timing gen-
erator option.
Private Memory
The user may partition the 16 K x 8 private memory
addressing space between :
- Page of character codes (2 K x 8 or 3 K x 8),
- External character generators,
- General purpose user area.
Many types of memory components are suitable :
- ROM, DRAM or SRAM,
- 2 K x 8, 8 K x 8, 16 K x 4 organizations,
- Modest 500ns cycle time and 250ns access time
is required.
40 Characters per Row : Character Code
Formats and Attributes
Once the 40 characters per row format has been
selected, one character code format out of three
must be chosen :
- 24-bit fixed format :
All the attributes are provided in parallel.
- 8/24-bit compressed format :
All the attributes are latched.
- 16-bit fixed format :
Some parallel attributes, other are latched.
Character attributes provided :
- Background and foreground color (3 bits each),
- Double height, double width,
- Blinking,
- Reverse,
- Underlining,
- Conceal,
- Insert,
- Accentuation of lower case characters,
- 3 x 100 user definable character generator in
memory,
- 8 x 100 semi-graphic quadrichrome characters.
80 Characters per Row Format : Character
Code Format and Attributes
Two character code formats are provided :
- Long (12 bits) with 4 parallel attributes :
• Blinking,
• Underlining,
• Reverse,
• Color select.
- Short (8 bits) : no attributes.
Timing Generator
The whole timing is derived from a 12MHz main
clock input.
The RGB outputs are shifted at 8MHz for the 40
character/row format and at 12MHz for the 80
character/row.
Besides, the user may select :
- 50Hz or 60Hz vertical sync. frequency,
- Interlaced or not,
- Separated or composite vertical and horizontal
sync. ouputs.
Furthermore, a composite sync. input allows, when
it is required :
- An on-chip vertical resynchronization,
- An on-chip crude horizontal resynchronization,
- An off-chip high performance horizontal resyn-
chronization by use of a simple external VCXO
controlled by the on-chip phase comparator.
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