Microchip Technology AC164127-9 Data Sheet
2011 Microchip Technology Inc.
DS01368A-page 17
AN1368
• DISPCLK is the clock which drives the display
glass.
• System clock is the clock speed at which the
program accesses the Command/Control/Status
registers.
registers.
• G1CLK is the clock which drives the GPUs to
draw lines, rectangles, render characters and
decode compressed data without the involvement
of the processor.
decode compressed data without the involvement
of the processor.
• External RAM, up to 16 MB, can be connected
through the EPMP module using a parallel inter-
face. The graphics module can use this on its own
without any involvement of the processor. The
interfaces allowed are limited to an 8-bit or 16-bit
parallel connection. For more options and informa-
tion, refer to Section 42. “Enhanced Parallel
Master Port (EPMP)”
face. The graphics module can use this on its own
without any involvement of the processor. The
interfaces allowed are limited to an 8-bit or 16-bit
parallel connection. For more options and informa-
tion, refer to Section 42. “Enhanced Parallel
Master Port (EPMP)”
(DS39730) in the “PIC24F
Family Reference Manual”
.
• HSYNC, VSYNC are the horizontal and vertical
synchronization signals to the display.
• GCLK is the pixel clock.
• GEN is a signal that varies in function for TFT and
• GEN is a signal that varies in function for TFT and
STN display types of interfaces. For TFT, this sig-
nal indicates that data lines are valid. For STN,
this signal toggles per line on the Line Toggle
mode and toggles per frame for the Frame Toggle
mode
nal indicates that data lines are valid. For STN,
this signal toggles per line on the Line Toggle
mode and toggles per frame for the Frame Toggle
mode
.
For more information, refer to Section 43.
“Graphics Controller Module (GFX)”
(DS39731) in the “PIC24F Family Reference
Manual”
Manual”
.
• GD<15:0> carry the display RGB or Gray values
as per the graphics module settings. Only the
required number of lines is enabled, depending
on the interface requirements of the display. (e.g.,
16 lined for TFT LCD’s RGB565 input or four lines
for MSTN’s grayscale input).
required number of lines is enabled, depending
on the interface requirements of the display. (e.g.,
16 lined for TFT LCD’s RGB565 input or four lines
for MSTN’s grayscale input).
• GPWR is the power supply control signal for the
display glass. In some large displays, an external
circuitry may be needed. Use this signal to enable
or disable the external power circuitry. In displays
that include an internal power circuitry, this signal
can be connected to the display’s power enable
pin. This signal should not be used as a power
supply line to the display glass.
circuitry may be needed. Use this signal to enable
or disable the external power circuitry. In displays
that include an internal power circuitry, this signal
can be connected to the display’s power enable
pin. This signal should not be used as a power
supply line to the display glass.
lists the number of microcontroller pins
required for various display and RAM configurations.
The Graphics Processing Units (GPUs) like the
Character Graphical Processing Unit (CHRGPU),
Rectangle Copy Graphics Processing Unit (RCCGPU)
and Inflate Processing Unit (IPU) are the graphics
accelerators. These accelerators are used for
rendering characters, rectangles and to decompress
the compressed data, respectively.
These GPUs help to free the processing power of the
microcontroller, which can be used for the purpose of
the application. Instead of the CPU rendering the
pixels, the application only needs to issue the
commands to draw primitive rendering functions (such
as lines, bars and characters) to the screen. After
issuing the commands, the CPU is free to perform
other application tasks. The application code runs in
parallel to the RCCGPU, which concurrently draws the
line. However, care should be taken because returning
from a function, for example, Line(), need not imply
that the line is completely drawn. This is called a non-
blocking draw. The drawing can also be made blocking
by setting the proper compiler switch in the
GraphicsConfig.h
The Graphics Processing Units (GPUs) like the
Character Graphical Processing Unit (CHRGPU),
Rectangle Copy Graphics Processing Unit (RCCGPU)
and Inflate Processing Unit (IPU) are the graphics
accelerators. These accelerators are used for
rendering characters, rectangles and to decompress
the compressed data, respectively.
These GPUs help to free the processing power of the
microcontroller, which can be used for the purpose of
the application. Instead of the CPU rendering the
pixels, the application only needs to issue the
commands to draw primitive rendering functions (such
as lines, bars and characters) to the screen. After
issuing the commands, the CPU is free to perform
other application tasks. The application code runs in
parallel to the RCCGPU, which concurrently draws the
line. However, care should be taken because returning
from a function, for example, Line(), need not imply
that the line is completely drawn. This is called a non-
blocking draw. The drawing can also be made blocking
by setting the proper compiler switch in the
GraphicsConfig.h
file, as explained in future
sections.
TABLE 4:
MICROCONTROLLER PINS
Configuration
Display Data
Pins (RGB)
EPMP
Pins
Other (Clock
and Sync)
Pins
Total
A TFT LCD without External RAM (using CLUT
and 16-bit colors)
and 16-bit colors)
16
0
5
21
A 256-Color CSTN without External RAM
8
0
5
13
A TFT LCD with External 16-Bit Wide RAM of
256 Kbytes (using 16-bit colors)
256 Kbytes (using 16-bit colors)
16
37
5
58
A 16-Color MSTN without External RAM
4
0
5
9