Datasheet

AN1368
DS01368A-page 8  2011 Microchip Technology Inc.
TABLE 2: BASIC COMPONENTS
For Options A and B, the Microchip Graphics Library
currently supports PIC24, dsPIC
®
and PIC32
microcontrollers with PMP or EPMP. The
PIC24FJXXXDAXXX family can support Options C and
D. PIC24FJ256DA210 contains 96 Kbytes of internal
memory and has a graphics controller inside. It also
supports optional external RAM as a frame buffer with
a parallel interface through the EPMP module. For
more information on the device, refer to the respective
device data sheet and also Section 43. “Graphics
Controller Module (GFX)” (DS39731) from the
“PIC24F Family Reference Manual”.
Options Advantages Disadvantages
A. The frame buffer and display
controller are housed in a single
module, called the ‘Display Module’.
The microcontroller and display
module interface through a serial or
parallel interface.
(1)
• No specific IC is required for graphics
functionality
• Less system components and less PCB
space
• Generally higher cost
• Usually forces a
software driver change
if the display module is
changed
• May lack additional
memory required for
double-buffering,
animation, etc.
B. The frame buffer is housed
together with the display controller.
The microcontroller and graphics
controller communicate through a
serial or parallel interface, whereas
the graphics controller interfaces to
the display glass through an RGB
interface.
(1)
• Software driver change is not required if
the display glass is changed. Only a
compile-time configuration change may be
needed.
• Can be cheaper than Option A
• More system compo-
nents and more PCB
space
• Display size is limited
by the frame buffer
inside the display
controller
C. The frame buffer and display
controller are housed inside the
microcontroller. The microcontroller
interfaces to the display glass
through an RGB interface.
Instead of a display controller, a
combination of a parallel interface
and a DMA engine can be used as
well.
• Only one IC is required for graphics
functionality
• Small form factor
• Usually the cheapest option
• Faster rendering since the memory is inside
the microcontroller
• Software driver change is not required if the
display module is changed. Only a
compile-time configuration change may be
needed.
• Display size is limited
by the frame buffer
inside the
microcontroller
D. The display controller is housed
inside the microcontroller. Separate
RAM is used as the frame buffer.
The microcontroller interfaces to the
display glass (display panel) through
an RGB interface and interfaces with
the frame buffer through a parallel
interface.
Instead of a display controller, a
combination of a parallel interface
and a DMA engine can be used as
well.
• The microcontroller can support the
maximum display size possible as the size
of the frame buffer can be selected by the
user
• Usually cheaper than Option A and B
• Requires an extra IC
chip for the frame
buffer
Note 1: A serial connection can be used on low resolution displays with low color depth (e.g., 1 BPP, 120x64). With
higher resolutions, the speed can be a bottleneck.