PIC16F627-04/P Microchip Technology Inc., PIC16F627-04/P Datasheet - Page 31

• Manufacturer Part Number: PIC16F627-04/P
• Description: 18 PIN, 1.75 KB FLASH, 224 RAM, 16 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F627-04/P

• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 128 Bytes
• Input Output: 16
• Interface: SCI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 18-pin PDIP
• Programmable Memory: 1.75K Bytes
• Ram Size: 224 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

5.0
The PIC16F62X have two ports, PORTA and PORTB.
Some pins for these I/O ports are multiplexed with an
alternate function for the peripheral features on the
device. In general, when a peripheral is enabled, that
pin may not be used as a general purpose I/O pin.
5.1
PORTA is an 8-bit wide latch. RA4 is a Schmitt Trigger
input and an open drain output. Port RA4 is multiplexed
with the T0CKI clock input. RA5 is a Schmitt Trigger
input only and has no output drivers. All other RA port
pins have Schmitt Trigger input levels and full CMOS
output drivers. All pins have data direction bits (TRIS
registers) which can configure these pins as input or
output.
A '1' in the TRISA register puts the corresponding out-
put driver in a Hi-impedance mode. A '0' in the TRISA
register puts the contents of the output latch on the
selected pin(s).
Reading the PORTA register reads the status of the
pins whereas writing to it will write to the port latch. All
write operations are read-modify-write operations. So a
write to a port implies that the port pins are first read,
then this value is modified and written to the port data
latch.
The PORTA pins are multiplexed with comparator and
voltage reference functions. The operation of these
pins are selected by control bits in the CMCON
(comparator control register) register and the VRCON
(voltage reference control register) register. When
selected as a comparator input, these pins will read
as '0's.
 2003 Microchip Technology Inc.
Note:
I/O PORTS
PORTA and TRISA Registers
RA5 shares function with V
voltage levels are applied to RA5, the
device will enter Programming mode.
PP
. When V
Preliminary
PP
TRISA controls the direction of the RA pins, even when
they are being used as comparator inputs. The user
must make sure to keep the pins configured as inputs
when using them as comparator inputs.
The RA2 pin will also function as the output for the
voltage reference. When in this mode, the V
very high impedance output. The user must configure
TRISA<2> bit as an input and use high impedance
loads.
In one of the Comparator modes defined by the
CMCON register, pins RA3 and RA4 become outputs
of the comparators. The TRISA<4:3> bits must be
cleared to enable outputs to use this function.
EXAMPLE 5-1:
CLRF
MOVLW 0x07
MOVWF CMCON
BCF
BSF
MOVLW 0x1F
MOVWF TRISA
Note 1: On RESET, the TRISA register is set to all
PORTA
STATUS, RP1
STATUS, RP0;Select Bank1
2: TRISA<6:7> is overridden by oscillator
inputs. The digital inputs are disabled and
the comparator inputs are forced to
ground to reduce current consumption.
configuration. When PORTA<6:7> is
overridden, the data reads ‘0’ and the
TRISA<6:7> bits are ignored.
;Initialize PORTA by
;setting output data latches
;Turn comparators off and
;enable pins for I/O
;functions
;Value used to initialize
;data direction
;Set RA<4:0> as inputs
;TRISA<5> always
;read as ‘1’.
;TRISA<7:6>
;depend on oscillator mode
Initializing PORTA
PIC16F62X
DS40300C-page 29
REF
pin is a