PIC18C858-E/L Microchip Technology, PIC18C858-E/L Datasheet - Page 89

• Manufacturer Part Number: PIC18C858-E/L
• Description: IC MCU OTP 16KX16 CAN 84PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 18Cr

Specifications of PIC18C858-E/L

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 68
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: OTP
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 84-PLCC
• For Use With: AC164310 - MODULE SKT FOR PM3 84PLCCDVA18XL840 - ADAPTER DEVICE ICE 84PLCCAC174012 - MODULE SKT PROMATEII 84PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: PIC18C858E/L

8.0
Depending on the device selected, there are up to
eleven ports available. Some pins of the I/O ports are
multiplexed with an alternate function from the periph-
eral features on the device. In general, when a periph-
eral 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.
8.1
PORTA is a 6-bit wide, bi-directional 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
hi-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).
On a Power-on Reset, these pins are configured as
inputs and read as '0'.
Reading the PORTA register reads the status of the
pins, whereas writing to it will write to the port latch.
Read-modify-write operations on the LATA register,
reads and writes the latched output value for PORTA.
The RA4 pin is multiplexed with the Timer0 module
clock input to become the RA4/T0CKI pin. The
RA4/T0CKI pin is a Schmitt Trigger input and an open
drain output. All other RA port pins have TTL input lev-
els and full CMOS output drivers.
The other PORTA pins are multiplexed with analog
inputs and the analog V
operation of each pin is selected by clearing/setting the
control bits in the ADCON1 register (A/D Control
Register1). On a Power-on Reset, these pins are con-
figured as analog inputs and read as '0'.
The TRISA register controls the direction of the RA
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.
 2000 Microchip Technology Inc.
device)
data
I/O PORTS
PORTA, TRISA and LATA Registers
latch
(LAT
REF
register)
+ and V
REF
is
- inputs. The
Advanced Information
useful
for
EXAMPLE 8-1:
FIGURE 8-1:
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
WR TRISA
WR LATA
or
WR PORTA
Note 1:
Data
Bus
RD PORTA
To A/D Converter and LVD Modules
SS Input (RA5 only)
PORTA
LATA
0x07
ADCON1
0xCF
TRISA
I/O pins have diode protection to V
Data Latch
D
D
TRIS Latch
CK
CK
RA3:RA0 AND RA5 PINS
BLOCK DIAGRAM
RD LATA
; Initialize PORTA by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Configure A/D
; for digital inputs
; Value used to
; initialize data
; direction
; Set RA3:RA0 as inputs
; RA5:RA4 as outputs
INITIALIZING PORTA
Q
Q
Q
Q
RD TRISA
PIC18CXX8
Q
Analog
Input
Mode
EN
DS30475A-page 89
D
V
DD
V
P
N
SS
DD
and V
TTL
Input
Buffer
I/O Pin
SS
.
(1)