MA240029 Microchip Technology, MA240029 Datasheet - Page 33

• Manufacturer Part Number: MA240029
• Description: Daughter Cards & OEM Boards PIC24FJ128GA310 Gen Purpose PIM
• Manufacturer: Microchip Technology

Specifications of MA240029

• Rohs: yes
• Product: Daughter Cards
• Core: PIC
• Description/function: Plug-in module
• Interface Type: I2C, SPI
• Tool Is For Evaluation Of: PIC24FJ128GA310
• For Use With: Explorer 16 Development Board

2.6
Many microcontrollers have options for at least two
oscillators: a high-frequency primary oscillator and a
low-frequency
Section 9.0 “Oscillator Configuration”
The oscillator circuit should be placed on the same
side of the board as the device. Place the oscillator
circuit close to the respective oscillator pins with no
more than 0.5 inch (12 mm) between the circuit
components and the pins. The load capacitors should
be placed next to the oscillator itself, on the same side
of the board.
Use a grounded copper pour around the oscillator cir-
cuit to isolate it from surrounding circuits. The
grounded copper pour should be routed directly to the
MCU ground. Do not run any signal traces or power
traces inside the ground pour. Also, if using a two-sided
board, avoid any traces on the other side of the board
where the crystal is placed.
Layout suggestions are shown in
packages may be handled with a single-sided layout
that completely encompasses the oscillator pins. With
fine-pitch packages, it is not always possible to com-
pletely surround the pins and components. A suitable
solution is to tie the broken guard sections to a mirrored
ground layer. In all cases, the guard trace(s) must be
returned to ground.
In planning the application’s routing and I/O assign-
ments, ensure that adjacent port pins, and other
signals in close proximity to the oscillator, are benign
(i.e., free of high frequencies, short rise and fall times
and other similar noise).
For additional information and design guidance on
oscillator circuits, please refer to these Microchip
Application Notes, available at the corporate web site
(www.microchip.com):
• AN826, “Crystal Oscillator Basics and Crystal
• AN849, “Basic PICmicro
• AN943, “Practical PICmicro
• AN949, “Making Your Oscillator Work”
 2010-2011 Microchip Technology Inc.
Selection for rfPIC™ and PICmicro
and Design”
External Oscillator Pins
secondary
®
Oscillator Design”
®
oscillator
Oscillator Analysis
Figure
®
Devices”
for details).
2-5. In-line
(refer
PIC24FJ128GA310 FAMILY
to
FIGURE 2-5:
(tied to ground)
Bottom Layer
Copper Pour
Oscillator
Secondary
Primary
Oscillator
Crystal
GND
OSCO
OSCI
C1
C2
Sec Oscillator: C1
DEVICE PINS
(tied to ground)
Single-Sided and In-line Layouts:
Copper Pour
Fine-Pitch (Dual-Sided) Layouts:
`
`
Top Layer Copper Pour
SUGGESTED
PLACEMENT OF THE
OSCILLATOR CIRCUIT
(tied to ground)
`
Primary Oscillator
Sec Oscillator: C2
Crystal
DEVICE PINS
DS39996F-page 33
C2
C1
OSCI
OSCO
GND
SOSCO
SOSC I
Oscillator
Crystal