DVR datasheet(126/416 Pages) MICROCHIP

126 / 416 page

PIC24FJ256GA705 FAMILY

DS30010118D-page 126

 2016-2018 Microchip Technology Inc.

11.1.1

I/O PORT WRITE/READ TIMING

One instruction cycle is required between a port

direction change or port write operation and a read

operation of the same port. Typically, this instruction

would be a NOP.

11.1.2

OPEN-DRAIN CONFIGURATION

In addition to the PORTx, LATx and TRISx registers for

data control, each port pin can also be individually

configured for either a digital or open-drain output. This

is controlled by the Open-Drain Control register, ODCx,

associated with each port. Setting any of the bits con-

figures the corresponding pin to act as an open-drain

output.

The open-drain feature allows the generation of

outputs higher than VDD (e.g., 5V) on any desired

digital only pins by using external pull-up resistors. The

maximum open-drain voltage allowed is the same as

the maximum VIH specification.

11.2 Configuring Analog Port Pins (ANSx)

The ANSx and TRISx registers control the operation of

the pins with analog function. Each port pin with analog

function is associated with one of the ANSx bits, which

decide if the pin function should be analog or digital.

Refer to Table 11-1 for detailed behavior of the pin for

different ANSx and TRISx bit settings.

When reading the PORTx register, all pins configured as

analog input channels will read as cleared (a low level).

11.2.1

ANALOG INPUT PINS AND

VOLTAGE CONSIDERATIONS

The voltage tolerance of pins used as device inputs is

dependent on the pin’s input function. Most input pins

are able to handle DC voltages of up to 5.5V, a level typ-

ical for digital logic circuits. However, several pins can

only tolerate voltages up to VDD. Voltage excursions

beyond VDD on these pins should always be avoided.

Table 11-2 summarizes the different voltage toler-

ances. For more information, refer to Section 32.0

“Electrical Characteristics” for more details.

TABLE 11-1:

CONFIGURING ANALOG/DIGITAL FUNCTION OF AN I/O PIN

Pin Function

ANSx Setting

TRISx Setting

Comments

Analog Input

It is recommended to keep ANSx = 1.

Analog Output

It is recommended to keep ANSx = 1.

Digital Input

Firmware must wait at least one instruction cycle

after configuring a pin as a digital input before a valid

input value can be read.

Digital Output

Make sure to disable the analog output function on

the pin if any is present.

TABLE 11-2:

INPUT VOLTAGE LEVELS FOR PORT OR PIN TOLERATED DESCRIPTION INPUT

Port or Pin

Tolerated Input

Description

PORTB<11:10,8:5>

5.5V

Tolerates input levels above VDD; useful

for most standard logic.

PORTC<9:6>

PORTA<14:7,4:0>

VDD

Only VDD input levels are tolerated.

PORTB<15:12,9,4:0>

PORTC<5:0>

DVR 数据表(PDF) 126 Page - Microchip Technology

DVR 数据表(HTML) 126 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

数据表下载