PIC16F819-I/SO Microchip Technology Inc., PIC16F819-I/SO Datasheet - Page 41

• Manufacturer Part Number: PIC16F819-I/SO
• Description: 18 PIN, 3.5 KB FLASH, 256 RAM, 16 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F819-I/SO

• A/d Inputs: 5-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 16
• Interface: I2C/SPI
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 18-pin SOIC
• Programmable Memory: 3.5K Bytes
• Ram Size: 256 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
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.
Additional information on I/O ports may be found in the
“PICmicro
Manual” (DS33023).
5.1
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. 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.
TABLE 5-1:
TABLE 5-2:
 2004 Microchip Technology Inc.
05h
85h
9Fh
Legend:
Note 1:
RA0/AN0
RA1/AN1
RA2/AN2/V
RA3/AN3/V
RA4/AN4/T0CKI
RA5/MCLR/V
RA6/OSC2/CLKO
RA7/OSC1/CLKI
Legend: TTL = TTL input, ST = Schmitt Trigger input
Note 1:
Address
Note:
Name
I/O PORTS
PORTA and the TRISA Register
®
PORTA
TRISA
ADCON1
x = unknown, u = unchanged, - = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.
Pin 5 is an input only; the state of the TRISA5 bit has no effect and will always read ‘1’.
This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.
On
PORTA<4:0> are configured as analog
inputs and read as ‘0’.
REF
REF
Name
Mid-Range
PP
-
+
a
PORTA FUNCTIONS
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
TRISA7 TRISA6 TRISA5
Bit#
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
Power-on
ADFM
Bit 7
RA7
MCU
ST/CMOS
ADCS2
Buffer
Bit 6
RA6
TTL
TTL
TTL
TTL
ST
ST
ST
Reset,
Family
(1)
Bit 5
RA5
—
Input/output or analog input.
Input/output or analog input.
Input/output, analog input or V
Input/output, analog input or V
Input/output, analog input or external clock input for Timer0.
Input, Master Clear (Reset) or programming voltage input.
Input/output, connects to crystal or resonator, oscillator output or 1/4 the
frequency of OSC1 and denotes the instruction cycle in RC mode.
Input/output, connects to crystal or resonator or oscillator input.
the
Reference
(1)
PORTA Data Direction Register
pins
Bit 4
RA4
—
PCFG3 PCFG2 PCFG1
Bit 3
RA3
Pin RA4 is multiplexed with the Timer0 module clock
input and with an analog input to become the RA4/AN4/
T0CKI pin. The RA4/AN4/T0CKI pin is a Schmitt
Trigger input and full CMOS output driver.
Pin RA5 is multiplexed with the Master Clear module
input. The RA5/MCLR/V
Pin RA6 is multiplexed with the oscillator module input
and external oscillator output. Pin RA7 is multiplexed
with the oscillator module input and external oscillator
input. Pin RA6/OSC2/CLKO and pin RA7/OSC1/CLKI
are Schmitt Trigger inputs and full CMOS output drivers.
Pins RA<1:0> are multiplexed with analog inputs. Pins
RA<3:2> are multiplexed with analog inputs and V
inputs. Pins RA<3:0> have TTL inputs and full CMOS
output drivers.
EXAMPLE 5-1:
BANKSEL PORTA
CLRF
BANKSEL ADCON1
MOVLW
MOVWF
MOVLW
MOVWF
Bit 2
RA2
REF-
REF+.
Bit 1
RA1
PORTA
0x06
ADCON1
0xFF
TRISA
Function
.
PIC16F818/819
PCFG0
Bit 0
RA0
INITIALIZING PORTA
; select bank of PORTA
; Initialize PORTA by
; clearing output
; data latches
; Select Bank of ADCON1
; Configure all pins
; as digital inputs
; Value used to
; initialize data
; direction
; Set RA<7:0> as inputs
PP
pin is a Schmitt Trigger input.
xxx0 0000
1111 1111
00-- 0000
POR, BOR
Value on
DS39598E-page 39
other Resets
Value on all
uuu0 0000
1111 1111
00-- 0000
REF