PIC16F887-I/PT Microchip Technology Inc., PIC16F887-I/PT Datasheet - Page 61

• Manufacturer Part Number: PIC16F887-I/PT
• Description: MCU, 8-Bit, 8KW Flash, 368 RAM, 36 I/O, TQFP-44
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F887-I/PT

• A/d Inputs: 14-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Frequency: 20 MHz
• Input Output: 35
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin TFQP
• Programmable Memory: 14K Bytes
• Ram Size: 368 Bytes
• Resistance, Drain To Source On: Bytes
• Serial Interface: MSSP or EUSART
• 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

3.7
PORTE
corresponding data direction register is TRISE. Setting a
TRISE bit (= 1) will make the corresponding PORTE pin
an input (i.e., put the corresponding output driver in a
High-Impedance mode). Clearing a TRISE bit (= 0) will
make the corresponding PORTE pin an output (i.e.,
enable the output driver and put the contents of the
output latch on the selected pin). The exception is RE3,
which is input only and its TRIS bit will always read as
‘1’. Example 3-6 shows how to initialize PORTE.
Reading the PORTE register (Register 3-13) 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. RE3 reads ‘0’ when MCLRE =
1.
REGISTER 3-13:
REGISTER 3-14:
© 2007 Microchip Technology Inc.
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7-4
bit 3-0
bit 7
Legend:
R = Readable bit
-n = Value at POR
bit 7-4
bit 3-0
Note 1:
Note 1: RE<2:0>
U-0
U-0
—
—
(1)
PORTE and TRISE Registers
is a 4-bit wide, bidirectional port. The
TRISE<3> always reads ‘1’.
PIC16F884/887 only.
Unimplemented: Read as ‘0’
RD<3:0>: PORTE General Purpose I/O Pin bit
1 = Port pin is > V
0 = Port pin is < V
Unimplemented: Read as ‘0’
TRISE<3:0>: PORTE Tri-State Control bit
1 = PORTE pin configured as an input (tri-stated)
0 = PORTE pin configured as an output
U-0
U-0
—
—
PORTE: PORTE REGISTER
TRISE: PORTE TRI-STATE REGISTER
pins
W = Writable bit
‘1’ = Bit is set
W = Writable bit
‘1’ = Bit is set
are
IH
IL
U-0
U-0
—
—
available
PIC16F882/883/884/886/887
U-0
U-0
Preliminary
—
—
on
U = Unimplemented bit, read as ‘0’
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
‘0’ = Bit is cleared
TRISE3
R-1
The TRISE register (Register 3-14) controls the PORTE
pin output drivers, even when they are being used as
analog inputs. The user should ensure the bits in the
TRISE register are maintained set when using them as
analog inputs. I/O pins configured as analog input always
read ‘0’.
EXAMPLE 3-6:
RE3
BANKSEL PORTE
CLRF
BANKSEL ANSEL
CLRF
BCF
BANKSEL TRISE
MOVLW
MOVWF
R-x
Note:
(1)
PORTE
ANSEL
STATUS,RP1
B‘00001100’
TRISE
The ANSEL register must be initialized to
configure an analog channel as a digital
input. Pins configured as analog inputs will
read ‘0’.
TRISE2
R/W-1
R/W-x
RE2
INITIALIZING PORTE
;
;Init PORTE
;
;digital I/O
;Bank 1
;
;Set RE<3:2> as inputs
;and set RE<1:0>
;as outputs
x = Bit is unknown
x = Bit is unknown
TRISE1
R/W-x
R/W-1
RE1
DS41291D-page 59
TRISE0
R/W-1
R/W-x
RE0
bit 0
bit 0