PIC16 datasheet(50/418 Pages) MICROCHIP

50 / 418 page

PIC16(L)F1508/9

DS40001609C-page 50

 2011-2013 Microchip Technology Inc.

FIGURE 5-3:

QUARTZ CRYSTAL

OPERATION (LP, XT OR

HS MODE)

FIGURE 5-4:

CERAMIC RESONATOR

OPERATION

(XT OR HS MODE)

5.2.1.3

Oscillator Start-up Timer (OST)

If the oscillator module is configured for LP, XT or HS

modes, the Oscillator Start-up Timer (OST) counts

1024 oscillations from OSC1. This occurs following a

Power-On Reset (POR) and when the Power-up Timer

(PWRT) has expired (if configured), or a wake-up from

Sleep. During this time, the program counter does not

increment and program execution is suspended,

unless either FSCM or Two-Speed Start-Up are

enabled. In this case, code will continue to execute at

the selected INTOSC frequency while the OST is

counting. The OST ensures that the oscillator circuit,

using a quartz crystal resonator or ceramic resonator,

has started and is providing a stable system clock to

the oscillator module.

In order to minimize latency between external oscillator

start-up and code execution, the Two-Speed Clock

Start-up mode can be selected (see Section 5.4

“Two-Speed Clock Start-up Mode”).

Note 1: Quartz

crystal

characteristics

vary

according

type,

package

and

manufacturer. The user should consult the

manufacturer data sheets for specifications

and recommended application.

2: Always verify oscillator performance over

the VDD and temperature range that is

expected for the application.

3: For oscillator design assistance, reference

the following Microchip Applications Notes:

• AN826, “Crystal Oscillator Basics and

Crystal Selection for rfPIC® and PIC®

Devices” (DS00826)

• AN849, “Basic PIC® Oscillator Design”

(DS00849)

• AN943, “Practical PIC® Oscillator

Analysis and Design” (DS00943)

• AN949, “Making Your Oscillator Work”

(DS00949)

(1)

OSC1/CLKIN

PIC

® MCU

OSC2/CLKOUT

Note 1:

A series resistor (Rs) may be required for

quartz crystals with low drive level.

The value of RF varies with the Oscillator mode

selected (typically between 2 MΩ and 10 MΩ).

(2)

To Internal

Logic

Sleep

Quartz

Crystal

Rev. 10-000059A

7/30/2013

(1)

OSC1/CLKIN

PIC

® MCU

OSC2/CLKOUT

Note 1:

A series resistor (Rs) may be required for

ceramic resonators with low drive level.

The value of RF varies with the Oscillator mode

selected (typically between 2 MΩ and 10 MΩ).

An additional parallel feedback resistor (RP)

may be required for proper ceramic resonator

operation.

(2)

To Internal

Logic

Sleep

(3)

Ceramic

Resonator

Rev. 10-000060A

7/30/2013

PIC16 датащи(PDF) 50 Page - Microchip Technology

PIC16 датащи(HTML) 50 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL