Datasheet

 2015 Microchip Technology Inc. Preliminary DS60001320B-page 37
PIC32MZ Embedded Connectivity with Floating Point Unit (EF) Family
2.0 GUIDELINES FOR GETTING
STARTED WITH 32-BIT
MICROCONTROLLERS
2.1 Basic Connection Requirements
Getting started with the PIC32MZ EF family of 32-bit
Microcontrollers (MCUs) requires attention to a minimal
set of device pin connections before proceeding with
development. The following is a list of pin names, which
must always be connected:
•All VDD and VSS pins (see 2.2 “Decoupling
Capacitors”)
•All AVDD and AVSS pins, even if the ADC module
is not used (see
2.2 “Decoupling Capacitors”)
• MCLR pin (see 2.3 “Master Clear (MCLR) Pin”)
• PGECx/PGEDx pins, used for In-Circuit Serial
Programming™ (ICSP™) and debugging pur
-
poses (see 2.4 “ICSP Pins”)
• OSC1 and OSC2 pins, when external oscillator
source is used (see
2.7 “External Oscillator
Pins”)
The following pin(s) may be required as well:
VREF+/VREF- pins, used when external voltage
reference for the ADC module is implemented.
2.2 Decoupling Capacitors
The use of decoupling capacitors on power supply
pins, such as V
DD, VSS, AVDD and AVSS is required.
See
Figure 2-1.
Consider the following criteria when using decoupling
capacitors:
• Value and type of capacitor: A value of 0.1 µF
(100 nF), 10-20V is recommended. The capacitor
should be a low Equivalent Series Resistance (low-
ESR) capacitor and have resonance frequency in
the range of 20
MHz and higher. It is further
recommended that ceramic capacitors be used.
• Placement on the printed circuit board: The
decoupling capacitors should be placed as close to
the pins as possible. It is recommended that the
capacitors be placed on the same side of the board
as the device. If space is constricted, the capacitor
can be placed on another layer on the PCB using a
via; however, ensure that the trace length from the
pin to the capacitor is within one-quarter inch
(6
mm) in length.
• Handling high frequency noise: If the board is
experiencing high frequency noise, upward of tens
of MHz, add a second ceramic-type capacitor in par-
allel to the above described decoupling capacitor.
The value of the second capacitor can be in the
range of 0.01 µF to 0.001 µF. Place this second
capacitor next to the primary decoupling capacitor.
In high-speed circuit designs, consider implement-
ing a decade pair of capacitances as close to the
power and ground pins as possible. For example,
0.1 µF in parallel with 0.001 µF.
• Maximizing performance: On the board layout
from the power supply circuit, run the power and
return traces to the decoupling capacitors first, and
then to the device pins. This ensures that the decou
-
pling capacitors are first in the power chain. Equally
important is to keep the trace length between the
capacitor and the power pins to a minimum thereby
reducing PCB track inductance.
Note 1: This data sheet summarizes the
features of the PIC32MZ EF family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to the “PIC32 Family
Reference Manual”, which is available
from the Microchip web
site
(
www.microchip.com/PIC32).
Note: The AVDD and AVSS pins must be
connected, regardless of ADC use and
the ADC voltage reference source.