PIC18LF8490-I/PT Microchip Technology, PIC18LF8490-I/PT Datasheet - Page 111

• Manufacturer Part Number: PIC18LF8490-I/PT
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,TQFP,80PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF8490-I/PT

• Rohs Compliant: YES
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, LCD, POR, PWM, WDT
• Number Of I /o: 66
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TFQFP
• Processor Series: PIC18LF
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: SPI, I2C, EUSART, AUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 66
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DV164136, DM163028
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

9.0
Depending on the device selected and features
enabled, there are up to nine ports available. Some
pins of the I/O ports are multiplexed with an alternate
function from 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.
Each port has three registers for its operation. These
registers are:
• TRIS register (data direction register)
• PORT register (reads the levels on the pins of the
• LAT register (output latch)
The
read-modify-write operations on the value that the I/O
pins are driving.
A simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in Figure 9-1.
FIGURE 9-1:
© 2007 Microchip Technology Inc.
device)
Note 1:
RD LAT
Data
Bus
WR LAT
or PORT
WR TRIS
RD TRIS
RD PORT
Data
I/O PORTS
I/O pins have diode protection to V
Latch
TRIS Latch
Data Latch
D
D
CK
CK
(LAT
GENERIC I/O PORT
OPERATION
Q
Q
register)
Q
EN
EN
D
DD
is
and V
useful
I/O pin
Buffer
Input
PIC18F6390/6490/8390/8490
SS
.
(1)
for
9.1
PORTA is an 8-bit wide, bidirectional port. The corre-
sponding Data Direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
high-impedance mode). Clearing a TRISA bit (= 0) will
make the corresponding PORTA pin an output (i.e., put
the contents of the output latch on the selected pin).
Reading the PORTA register reads the status of the
pins, whereas writing to it will write to the port latch.
The Data Latch register (LATA) is also memory mapped.
Read-modify-write operations on the LATA register read
and write the latched output value for PORTA.
The RA4 pin is multiplexed with the Timer0 module
clock input and the LCD segment drive to become the
RA4/T0CKI/SEG14 pin. Pins RA6 and RA7 are
multiplexed with the main oscillator pins; they are
enabled as oscillator or I/O pins by the selection of the
main oscillator in the Configuration register (see
Section 23.1 “Configuration Bits” for details). When
they are not used as port pins, RA6 and RA7 and their
associated TRIS and LAT bits are read as ‘0’.
The other PORTA pins are multiplexed with analog
inputs and the analog V
operation of pins RA3:RA0 and RA5 as A/D converter
inputs is selected by clearing or setting the control bits
in the ADCON1 register (A/D Control Register 1).
The RA4/T0CKI/SEG14 pin is a Schmitt Trigger input
and an open-drain output. All other PORTA pins have
TTL input levels and full CMOS output drivers.
The TRISA register controls the direction of the PORTA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
RA5:RA2 are also multiplexed with LCD segment
drives controlled by bits in the LCDSE1 and
LCDSE2 registers. I/O port functions are only
available when the segments are disabled.
EXAMPLE 9-1:
CLRF
CLRF
MOVLW
MOVWF
MOVWF
MOVWF
MOVLW
MOVWF
PORTA, TRISA and
LATA Registers
PORTA
LATA
07h
ADCON1 ; for digital inputs
07h
CMCON
0CFh
TRISA
; Initialize PORTA by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Configure A/D
; Configure comparators
; for digital input
; Value used to
; initialize data
; direction
; Set RA<3:0> as inputs
; RA<5:4> as outputs
INITIALIZING PORTA
REF
+ and V
DS39629C-page 109
REF
- inputs. The