PIC18F2320-I/SO Microchip Technology Inc., PIC18F2320-I/SO Datasheet - Page 106

• Manufacturer Part Number: PIC18F2320-I/SO
• Description: Microcontroller; 8 KB Flash; 512 RAM; 256 EEPROM; 25 I/O; 28-Pin-SOIC
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F2320-I/SO

• A/d Inputs: 10-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 25
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SOIC
• Programmable Memory: 8K Bytes
• Ram Size: 512 Bytes
• Speed: 20 MHz
• Timers: 1-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC18F2220/2320/4220/4320
10.2
PORTB is an 8-bit wide, bidirectional port. The corre-
sponding data direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB
pin an input (i.e., put the corresponding output driver in
a High-Impedance mode). Clearing a TRISB bit (= 0)
will make the corresponding PORTB pin an output (i.e.,
put the contents of the output latch on the selected pin).
The Data Latch register (LATB) is also memory
mapped. Read-modify-write operations on the LATB
register read and write the latched output value for
PORTB.
EXAMPLE 10-2:
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is per-
formed by clearing bit RBPU (INTCON2<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
Four of the PORTB pins (RB7:RB4) have an interrupt-
on-change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupt-
on-change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RB Port Change
Interrupt with Flag bit, RBIF (INTCON<0>).
DS39599C-page 104
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
Note:
PORTB, TRISB and LATB
Registers
PORTB
LATB
0x0F
ADCON1 ; digital I/O pins
0xCF
TRISB
On a Power-on Reset, RB4:RB0 are con-
figured as analog inputs by default and
read as ‘0’; RB7:RB5 are configured as
digital inputs.
By programming the configuration bit,
PBADEN (CONFIG3H<1>), RB4:RB0 will
alternatively be configured as digital inputs
on POR.
; Initialize PORTB by
; clearing output
; data latches
; Alternate method
; to clear output
; data latches
; Set RB<4:0> as
; (required if config bit
; PBADEN is set)
; Value used to
; initialize data
; direction
; Set RB<3:0> as inputs
; RB<5:4> as outputs
; RB<7:6> as inputs
INITIALIZING PORTB
This interrupt can wake the device from Sleep. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
b)
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
RB3 can be configured by the configuration bit,
CCP2MX, as the alternate peripheral pin for the CCP2
module (CCP2MX = 0).
FIGURE 10-6:
Note 1:
RB7:RB5 in Serial Programming Mode
Data Bus
or PORTB
RD PORTB
Set RBIF
RBPU
WR LATB
WR TRISB
RD TRISB
RD LATB
Any read or write of PORTB (except with the
MOVFF (ANY), PORTB instruction). This will
end the mismatch condition.
Clear flag bit RBIF.
RB7:RB5 and
From other
2:
RB4 pins
(2)
I/O pins have diode protection to V
To enable weak pull-ups, set the appropriate TRIS bit(s)
and clear the RBPU bit (INTCON2<7>).
TRIS Latch
Data Latch
D
D
CK
CK
BLOCK DIAGRAM OF
RB7:RB5 PINS
Q
Q
 2003 Microchip Technology Inc.
Q
Q
Latch
EN
EN
D
D
DD
TTL
Input
Buffer
and V
RD PORTB
V
P
DD
SS
Weak
Pull-up
I/O pin
.
Buffer
Q1
Q3
ST
(1)