PIC10F320 datasheet(76/210 Pages) MICROCHIP

76 / 210 page

PIC10(L)F320/322

DS41585A-page 76

Preliminary

 2011 Microchip Technology Inc.

10.1

PORTA Registers

PORTA is a 8-bit wide, bidirectional port. The

corresponding data direction register is TRISA

(Register 10-2). Setting a TRISA bit (= 1) will make the

corresponding PORTA pin an input (i.e., disable the

output driver). Clearing a TRISA bit (= 0) will make the

corresponding PORTA pin an output (i.e., enables

output driver and puts the contents of the output latch

on the selected pin). Example 10-1 shows how to

initialize PORTA.

Reading the PORTA register (Register 10-1) reads the

status of the pins, whereas writing to it will write to the

PORT latch. All write operations are read-modify-write

operations. Therefore, a write to a port implies that the

port pins are read, this value is modified and then

written to the PORT data latch (LATA).

The TRISA register (Register 10-2) controls the

PORTA pin output drivers, even when they are being

used as analog inputs. The user should ensure the bits

in the TRISA register are maintained set when using

them as analog inputs. I/O pins configured as analog

input always read ‘0’.

10.1.1

WEAK PULL-UPS

Each of the PORTA pins has an individually configu-

rable internal weak pull-up. Control bits WPUA<3:0>

enable or disable each pull-up (see Register 10-5).

Each weak pull-up is automatically turned off when the

port pin is configured as an output. All pull-ups are dis-

abled on a Power-on Reset by the WPUEN bit of the

OPTION_REG register.

10.1.2

ANSELA REGISTER

The ANSELA register (Register 10-4) is used to

configure the Input mode of an I/O pin to analog.

Setting the appropriate ANSELA bit high will cause all

digital reads on the pin to be read as ‘0’ and allow

analog functions on the pin to operate correctly.

The state of the ANSELA bits has no effect on digital

output functions. A pin with TRIS clear and ANSEL set

will still operate as a digital output, but the Input mode

will be analog. This can cause unexpected behavior

when executing read-modify-write instructions on the

affected port.

10.1.3

PORTA FUNCTIONS AND OUTPUT

PRIORITIES

Each PORTA pin is multiplexed with other functions. The

pins, their combined functions and their output priorities

are shown in Table 10-1.

When multiple outputs are enabled, the actual pin

control goes to the peripheral with the highest priority.

Digital output functions may control the pin when it is in

Analog mode with the priority shown in Table 10-1.

Note:

The ANSELA bits default to the Analog

mode after Reset. To use any pins as

digital general purpose or peripheral

inputs, the corresponding ANSEL bits

must be initialized to ‘0’ by user software.

TABLE 10-1:

PORTA OUTPUT PRIORITY

Pin Name

Function Priority(1)

RA0

ICSPDAT

CWG1A

PWM1

RA0

RA1

CWG1B

PWM2

CLC1

RA1

RA2

NCO1

CLKR

RA2

RA3

None

Note 1:

Priority listed from highest to lowest.

PIC10F320 датащи(PDF) 76 Page - Microchip Technology

PIC10F320 датащи(HTML) 76 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