PIC16F1939-I/PT Microchip Technology Inc., PIC16F1939-I/PT Datasheet - Page 142

• Manufacturer Part Number: PIC16F1939-I/PT
• Description: 44 TQFP 10x10x1mm TRAY, 28KB Flash, 1KB RAM, 256B EEPROM, LCD, 1.8-5.5V
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F1939-I/PT

• A/d Inputs: 14-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 8 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 36
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 40-pin TQFP
• Programmable Memory: 28K Bytes
• Ram Size: 1K Bytes
• Speed: 32 MHz
• Temperature Range: –40 to 125 °C
• Timers: 4-8-bit, 1-16-bit
• Voltage, Range: 1.8-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC16F193X/LF193X
12.5
PORTD is a 8-bit wide, bidirectional port. The
corresponding
(Register 12-14). Setting a TRISD bit (= 1) will make the
corresponding PORTD pin an input (i.e., put the
corresponding output driver in a High-Impedance mode).
Clearing a TRISD bit (= 0) will make the corresponding
PORTD pin an output (i.e., enable the output driver and
put the contents of the output latch on the selected pin).
Example 12-4 shows how to initialize PORTD.
Reading the PORTD register (Register 12-14) 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 (LATD).
The TRISD register (Register 12-15) controls the
PORTD pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits
in the TRISD register are maintained set when using
them as analog inputs. I/O pins configured as analog
input always read ‘0’.
12.5.1
The ANSELD register (Register 12-17) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELD 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 ANSELD bits has no affect 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.
EXAMPLE 12-4:
DS41364D-page 142
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
MOVLW
MOVWF
Note:
Note:
PORTD Registers
PORTD
PORTD
LATD
LATD
ANSELD
ANSELD
TRISD
B'11110000' ;Set RD<7:4> as inputs
TRISD
PORTD is available on PIC16F1936 and
PIC16F1938 only.
ANSELD REGISTER
The ANSELD register must be initialized
to configure an analog channel as a digital
input. Pins configured as analog inputs will
read ‘0’.
data
INITIALIZING PORTD
direction
;
;Init PORTD
;Data Latch
;
;
;digital I/O
;
;and set RD<3:0> as
;outputs
register
is
TRISD
Preliminary
12.5.2
Each PORTD pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are briefly described here. For additional information,
refer to the appropriate section in this data sheet.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the lowest number in
the following lists.
Analog input and some digital input functions are not
included in the list below. These input functions can
remain active when the pin is configured as an output.
Certain digital input functions override other port
functions and are included in the priority list.
RD0
1.
2.
RD1
1.
2.
RD2
1.
2.
RD3
1.
2.
3.
RD4
1.
2.
3.
RD5
1.
2.
3.
RD6
1.
2.
3.
RD7
1.
2.
3.
COM3 (LCD)
RD0
CCP4 (CCP)
RD1
P2B (CCP)
RD2
SEG16 (LCD)
P2C (CCP)
RD3
SEG17 (LCD)
P2D (CCP)
RD4
SEG18 (LCD)
P1B (CCP)
RD5
SEG19 (LCD)
P1C (CCP)
RD6
SEG20 (LCD)
P1D (CCP)
RD7
PORTD FUNCTIONS AND OUTPUT
PRIORITIES
 2009 Microchip Technology Inc.