PIC32MM0064GPL020-ISLASHML datasheet(21/268 Pages) MICROCHIP

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 2015-2016 Microchip Technology Inc.

DS60001324B-page 21

PIC32MM0064GPL036 FAMILY

2.5

ICSP Pins

The PGECx and PGEDx pins are used for In-Circuit

Serial Programming™ (ICSP™) and debugging pur-

poses. It is recommended to keep the trace length

between the ICSP connector and the ICSP pins on

the device as short as possible. If the ICSP connec-

tor is expected to experience an ESD event, a series

resistor is recommended, with the value in the range

of a few tens of Ohms, not to exceed 100 Ohms.

Pull-up resistors, series diodes and capacitors on the

PGECx and PGEDx pins are not recommended as they

will interfere with the programmer/debugger communi-

cations to the device. If such discrete components are

an application requirement, they should be removed

from the circuit during programming and debugging.

Alternatively, refer to the AC/DC characteristics and

timing requirements information in the respective

device Flash programming specification for information

on capacitive loading limits and pin Input Voltage High

(VIH) and Input Voltage Low (VIL) requirements.

Ensure that the “Communication Channel Select”

(i.e., PGECx/PGEDx pins) programmed into the device

matches the physical connections for the ICSP to

MPLAB® ICD 3 or MPLAB REAL ICE™ In-Circuit

Emulator.

For more information on MPLAB ICD 3 and REAL ICE

connection

requirements,

refer

the

following

documents that are available from the Microchip web site.

• “Using MPLAB® ICD 3 In-Circuit Debugger”

(poster) (DS51765)

• “Development Tools Design Advisory” (DS51764)

• “MPLAB® REAL ICE™ In-Circuit Emulator User’s

Guide” (

DS51616)

• “Using MPLAB® REAL ICE™ In-Circuit Emulator”

(poster) (DS51749)

2.6

JTAG

The TMS, TDO, TDI and TCK pins are used for testing

and debugging according to the Joint Test Action Group

(JTAG) standard. It is recommended to keep the trace

length between the JTAG connector, and the JTAG pins

on the device, as short as possible. If the JTAG connector

is expected to experience an ESD event, a series resistor

is recommended, with the value in the range of a few tens

of Ohms, not to exceed 100 Ohms.

Pull-up resistors, series diodes and capacitors on the

TMS, TDO, TDI and TCK pins are not recommended as

they will interfere with the programmer/debugger com-

munications to the device. If such discrete components

are an application requirement, they should be removed

from the circuit during programming and debugging.

Alternatively, refer to the AC/DC characteristics and

timing requirements information in the respective device

Flash programming specification for information on

capacitive loading limits, and pin Input Voltage High (VIH)

and Input Voltage Low (VIL) requirements.

2.7

External Oscillator Pins

The PIC32MM0064GPL036 family has options for two

external oscillators: a high-frequency primary oscillator

and a low-frequency secondary oscillator (refer to

Section 8.0 “Oscillator Configuration”

for details).

The oscillator circuit should be placed on the same side

of the board as the device. Also, place the oscillator

circuit close to the respective oscillator pins, not

exceeding one-half inch (12 mm) distance between

them. 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 circuit to

isolate them 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. A suggested layout is illustrated in

Figure 2-3.

FIGURE 2-3:

SUGGESTED OSCILLATOR

CIRCUIT PLACEMENT

2.8

Unused I/Os

To minimize power consumption, unused I/O pins

should not be allowed to float as inputs. They can be

configured as outputs and driven to a logic low or logic

high state.

Alternatively, inputs can be reserved by ensuring the

pin is always configured as an input and externally con-

necting the pin to VSS or VDD. A current-limiting resistor

may be used to create this connection if there is any

risk of inadvertently configuring the pin as an output

with the logic output state opposite of the chosen power

rail.

Main Oscillator

Guard Ring

Guard Trace

Secondary

Oscillator

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