PIC32MX データシートの表示（PDF） - Microchip Technology

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PIC32MX

32-bit Microcontrollers (up to 128 KB Flash and 32 KB SRAM) with Audio and Graphics Interfaces, USB, and Advanced Analog

Microchip Technology 

PIC32MX1XX/2XX

2.2.1 BULK CAPACITORS

The use of a bulk capacitor is recommended to improve

power supply stability. Typical values range from 4.7 µF

to 47 µF. This capacitor should be located as close to

the device as possible.

2.3 Capacitor on Internal Voltage

Regulator (VCAP)

2.3.1 INTERNAL REGULATOR MODE

A low-ESR (1 ohm) capacitor is required on the VCAP

pin, which is used to stabilize the internal voltage regu-

lator output. The VCAP pin must not be connected to

VDD, and must have a CEFC capacitor, with at least a

6V rating, connected to ground. The type can be

ceramic or tantalum. Refer to Section 29.0 “Electrical

Characteristics” for additional information on CEFC

specifications.

2.4 Master Clear (MCLR) Pin

The MCLR pin provides for two specific device

functions:

• Device Reset

• Device programming and debugging

Pulling The MCLR pin low generates a device Reset.

Figure 2-2 illustrates a typical MCLR circuit. During

device programming and debugging, the resistance

and capacitance that can be added to the pin must

be considered. Device programmers and debuggers

drive the MCLR pin. Consequently, specific voltage

levels (VIH and VIL) and fast signal transitions must

not be adversely affected. Therefore, specific values

of R and C will need to be adjusted based on the

application and PCB requirements.

For example, as illustrated in Figure 2-2, it is

recommended that the capacitor C, be isolated from

the MCLR pin during programming and debugging

operations.

Place the components illustrated in Figure 2-2 within

one-quarter inch (6 mm) from the MCLR pin.

FIGURE 2-2:

VDD

EXAMPLE OF MCLR PIN

CONNECTIONS(1,2,3)

R

R1

MCLR

JP

PIC32

C

Note 1: R ≤ 10 kΩ is recommended. A suggested

starting value is 10 kΩ. Ensure that the MCLR

pin VIH and VIL specifications are met.

2: R1 ≤ 470Ω will limit any current flowing into

MCLR from the external capacitor C, in the

event of MCLR pin breakdown, due to

Electrostatic Discharge (ESD) or Electrical

Overstress (EOS). Ensure that the MCLR pin

VIH and VIL specifications are met.

3: The capacitor can be sized to prevent uninten-

tional Resets from brief glitches or to extend

the device Reset period during POR.

DS61168C-page 28

Preliminary

© 2011 Microchip Technology Inc.

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