PIC16F870-I/SS Microchip Technology, PIC16F870-I/SS Datasheet - Page 35

• Manufacturer Part Number: PIC16F870-I/SS
• Description: IC MCU FLASH 2KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F870-I/SS

• Core Size: 8-Bit
• Program Memory Size: 3.5KB (2K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 64Byte
• Ram Memory Size: 128Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 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
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 28 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3-DB16F871 - BOARD DAUGHTER ICEPIC3AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details

4.0
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™ Mid-Range MCU Family Reference
Manual (DS33023).
4.1
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).
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, the
value is modified and then written to the port data latch.
Pin RA4 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 PORTA pins have TTL input levels and full
CMOS output drivers.
Other PORTA pins are multiplexed with analog inputs
and analog V
selected by clearing/setting the control bits in the
ADCON1 register (A/D Control Register 1).
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.
EXAMPLE 4-1:
 2003 Microchip Technology Inc.
BCF
BCF
CLRF
BSF
MOVLW
MOVWF
MOVLW
MOVWF
Note:
I/O PORTS
PORTA and the TRISA Register
STATUS, RP0
STATUS, RP1
PORTA
STATUS, RP0
0x06
ADCON1
0xCF
TRISA
On a Power-on Reset, these pins are
configured as analog inputs and read as
'0'.
REF
input. The operation of each pin is
INITIALIZING PORTA
;
;Bank0
;Initialize PORTA by
;clearing output
;data latches
;Select Bank 1
;Configure all pins
;as digital inputs
;Value used to
;initialize data
;direction
;Set RA<3:0> as
;inputs
;RA<5:4> as outputs
;TRISA<7:6> are
;always read as '0'.
FIGURE 4-1:
FIGURE 4-2:
Data
Bus
WR
Port
WR
TRIS
RD PORT
To A/D Converter
Note 1:
Note 1:
Data
Bus
WR
TRIS
WR
PORT
RD PORT
TMR0 Clock Input
I/O pins have protection diodes to V
I/O pin has protection diodes to V
TRIS Latch
D
Data Latch
D
CK
CK
Data Latch
TRIS Latch
PIC16F870/871
D
D
CK
CK
RD TRIS
Q
Q
Q
Q
RD TRIS
Q
Q
Q
Q
BLOCK DIAGRAM OF
RA3:RA0 AND RA5 PINS
BLOCK DIAGRAM OF
RA4/T0CKI PIN
Q
Q
EN
Analog
Input
Mode
EN
Schmitt
Trigger
Input
Buffer
D
EN
D
DS30569B-page 33
V
SS
N
SS
DD
V
V
only.
P
N
SS
DD
and V
I/O pin
TTL
Input
Buffer
SS
I/O pin
.
(1)
(1)