70592C datasheet(23/314 Pages) MICROCHIP

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DS70592C-page 23

PIC24HJXXXGPX06A/X08A/X10A

2.0

GUIDELINES FOR GETTING

STARTED WITH 16-BIT

MICROCONTROLLERS

2.1

Basic Connection Requirements

Getting

started

with

the

PIC24HJXXXGPX06A/X08A/X10A family of 16-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 Section 2.2 “Decoupling Capacitors”)

• All AVDD and AVSS pins (regardless if ADC module

is not used)

(see Section 2.2 “Decoupling Capacitors”)

•VCAP

(see Section 2.3 “CPU Logic Filter Capacitor

Connection (Vcap)”)

•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 2.6 “External Oscillator Pins”)

Additionally, the following pins may be required:

•VREF+/VREF- pins used when external voltage

reference for ADC module is implemented

2.2

Decoupling Capacitors

The use of decoupling capacitors on every pair of

power supply pins, such as VDD, VSS, AVDD and

AVSS is required.

Consider the following criteria when using decoupling

capacitors:

• Value and type of capacitor: Recommendation

of 0.1 µF (100 nF), 10-20V. This capacitor should

be a low-ESR and have resonance frequency in

the range of 20 MHz and higher. It is

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 to

place the capacitors 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 capaci-

tor 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.

Note 1: This data sheet summarizes the features

of the PIC24HJXXXGPX06A/X08A/X10A

family of devices. It is not intended to be

a comprehensive reference source. To

complement the information in this data

sheet, refer to the “dsPIC33F/PIC24H

Family Reference Manual”. Please see

the

Microchip

web

site

(www.microchip.com)

for

the

latest

dsPIC33F/PIC24H

Family

Reference

Manual sections.

2: Some registers and associated bits

described in this section may not be

available on all devices. Refer to

Section 4.0 “Memory Organization” in

this data sheet for device-specific register

and bit information.

Note:

The AVDD and AVSS pins must be

connected independent of the ADC

voltage reference source.

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