AN1368

DS01368A-page 8

 2011 Microchip Technology Inc.

TABLE 2:

BASIC COMPONENTS

For Options A and B, the Microchip Graphics Library

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

• 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

• 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.