PIC16F1947-I/PT Microchip Technology Inc., PIC16F1947-I/PT Datasheet - Page 127

• Manufacturer Part Number: PIC16F1947-I/PT
• Description: 64 TQFP 10x10x1mm TRAY28KB Flash, 1KB RAM, 256B EEPROM, LCD, 1.8-5.5V
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F1947-I/PT

• A/d Inputs: 17-Channel, 10-Bit
• Comparators: 3
• Cpu Speed: 8 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 54
• Interface: CAN/I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 64-pin TQFP
• Programmable Memory: 28K Bytes
• Ram Size: 1K Bytes
• Speed: 32 MHz
• Timers: 4-8-bit, 1-16-bit
• Voltage, Range: 1.8-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

12.2
PORTA is a 8-bit wide, bidirectional port. The
corresponding data direction register is TRISA
(Register
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).
initialize PORTA.
Reading the PORTA register
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
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’.
12.2.1
The ANSELA register
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 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 12-1:
 2010 Microchip Technology Inc.
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
CLRF
BANKSEL
MOVLW
MOVWF
Note:
PORTA Registers
12-3). Setting a TRISA bit (= 1) will make the
ANSELA REGISTER
PORTA
PORTA
LATA
LATA
ANSELA
ANSELA
TRISA
B'11110000' ;Set RA<7:4> as inputs
TRISA
The ANSELA register must be initialized
to configure an analog channel as a digital
input. Pins configured as analog inputs
will read ‘0’.
INITIALIZING PORTA
Example 12-1
(Register
(Register
;
;Init PORTA
;Data Latch
;
;
;digital I/O
;
;and set RA<3:0> as
;outputs
(Register
12-3) controls the
12-5) is used to
12-2) reads the
shows how to
Preliminary
12.2.2
Each PORTA 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 functions, such as ADC, comparator and
CapSense inputs, are not shown in the priority lists.
These inputs are active when the I/O pin is set for
Analog mode using the ANSELx registers. Digital
output functions may control the pin when it is in Analog
mode with the priority shown below.
RA0
1.
2.
3.
RA1
1.
2.
RA2
1.
2.
3.
4.
RA3
1.
2.
3.
4.
RA4
1.
2.
RA5
1.
2.
3.
RA6
1.
2.
3.
RA7
1.
2.
AN0 (ADC)
SEG33 (LCD)
CPS0 (CSM)
SEG18
CPS1 (CSM)
SEG34 (LCD)
V
AN2 (ADC)
CPS2 (CSM)
V
SEG35 (LCD)
AN3 (ADC)
CPS3 (CSM)
SEG14 (LCD)
T0CKI (TMR0)
AN4 (ADC)
SEG15 (LCD)
CPS4 (CSM)
OSC2 (enabled by Configuration Word)
CLKOUT (enabled by Configuration Word)
SEG36 (LCD)
OSC1/CLKIN (enabled by Configuration Word)
SEG37 (LCD)
REF
REF
PIC16F/LF1946/47
- (DAC)
+ (DAC)
PORTA FUNCTIONS AND OUTPUT
PRIORITIES
DS41414B-page 127