PIC32MX575F256H-80I Datasheet, PDF (35/236 Pages) Microchip Technology – High-Performance, USB, CAN and Ethernet 32-Bit Flash Microcontrollers

PIC32MX5XX/6XX/7XX
2.0 GUIDELINES FOR GETTING
STARTED WITH 32-BIT
MICROCONTROLLERS
Note 1: This data sheet summarizes the features
of the PIC32MX5XX/6XX/7XX family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to the related section of the
“PIC32MX Family Reference Manual”,
which is available from the Microchip web
site (www.microchip.com/PIC32)
2: Some registers and associated bits
described in this section may not be avail-
able on all devices. Refer to Section 4.0
“Memory Organization” in this data
sheet for device-specific register and bit
information.
2.1 Basic Connection Requirements
Getting started with the PIC32MX5XX/6XX/7XX family
of 32-bit Microcontrollers (MCU) requires attention to a
minimal set of device pin connections before proceed-
ing with development. The following is a list of pin
names, which must always be connected:
• All VDD and VSS pins
(see Section 2.2 “Decoupling Capacitors”)
• All AVDD and AVSS pins–even if the ADC module
is not used
(see Section 2.2 “Decoupling Capacitors”)
• VCAP/VDDCORE pin
(see Section 2.3 “Capacitor on Internal
Voltage Regulator (VCAP/VDDCORE)”)
• MCLR pin
(see Section 2.4 “Master Clear (MCLR) Pin”)
• PGECx/PGEDx pins–used for In-Circuit Serial
Programming (ICSP™) and debugging purposes
(see Section 2.5 “ICSP Pins”)
• OSC1 and OSC2 pins–when external oscillator
source is used
(see Section 2.8 “External Oscillator Pins”)
The following pin may be required, as well:
VREF+/VREF- pins–used when external voltage refer-
ence for ADC module is implemented
Note:
The AVDD and AVSS pins must be
connected, regardless of ADC use and the
ADC voltage reference source.
2.2 Decoupling Capacitors
The use of decoupling capacitors on power supply
pins, such as VDD, 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 fre-
quency 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 parallel 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
implementing 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
decoupling 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.
 2010 Microchip Technology Inc.
Preliminary
DS61156C-page 35