Datasheet

ManualsBrandsDIGILENT ManualsDev KitsPCB design board

PIC32MX5XX/6XX/7XX

DS60001156J-page 40  2009-2016 Microchip Technology Inc.

2.9 Configuration of Analog and

Digital Pins During ICSP

Operations

If MPLAB ICD 3 or REAL ICE is selected as a

debugger, it automatically initializes all of the Analog-

to-Digital input pins (ANx) as “digital” pins by setting

all bits in the AD1PCFG register.

The bits in this register that correspond to the Analog-

to-Digital pins that are initialized by MPLAB ICD 3 or

REAL ICE, must not be cleared by the user application

firmware; otherwise, communication errors will result

between the debugger and the device.

If your application needs to use certain ADC pins as

analog input pins during the debug session, the user

application must clear the corresponding bits in the

AD1PCFG register during initialization of the ADC

module.

When MPLAB ICD 3 or REAL ICE is used as a pro-

grammer, the user application firmware must correctly

configure the AD1PCFG register. Automatic initializa-

tion of this register is only done during debugger oper-

ation. Failure to correctly configure the register(s) will

result in all ADC pins being recognized as analog input

pins, resulting in the port value being read as a logic ‘0’,

which may affect user application functionality.

2.10 Unused I/Os

Unused I/O pins should not be allowed to float as

inputs. They can be configured as outputs and driven

to a logic-low state.

Alternatively, inputs can be reserved by connecting the

pin to V

through a 1k to 10k resistor and configuring

the pin as an input.

2.11 EMI/EMC/EFT (IEC 61000-4-4 and

IEC 61000-4-2) Suppression

Considerations

The use of LDO regulators is preferred to reduce

overall system noise and provide a cleaner power

source. However, when utilizing switching Buck/

Boost regulators as the local power source for PIC32

devices, as well as in electrically noisy environ-

ments or test conditions required for IEC 61000-4-4

and IEC 61000-4-2, users should evaluate the use of

T-Filters (i.e., L-C-L) on the power pins, as shown in

Figure 2-4. In addition to a more stable power

source, use of this type of T-Filter can greatly reduce

susceptibility to EMI sources and events.

FIGURE 2-4: EMI/EMC/EFT

SUPPRESSION CIRCUIT

USB3V3

Ferrite

Chips

0.01 μF

0.1 μF

Ferrite

Chips

Ferrite Chip SMD

DCR = 0.15ȍ (max)

600 ma ISAT

300ȍ @ 100 MHz

PN#: 1-1624117-3

0.1 μF

PIC32