PIC16F688T-I/SL Microchip Technology, PIC16F688T-I/SL Datasheet - Page 142

• Manufacturer Part Number: PIC16F688T-I/SL
• Description: IC MCU PIC FLASH 4KX14 14SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688T-I/SL

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Controller Family/series: PIC16F
• No. Of I/o's: 12
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 256Byte
• Cpu Speed: 20MHz
• No. Of Timers: 2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT14SO-1 - SOCKET TRANSITION 14SOIC 150/208AC162061 - HEADER INTRFC MPLAB ICD2 20PINAC162056 - HEADER INTERFACE ICD2 16F688
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: PIC16F688T-I/SL; PIC16F688T-I/SLTR

PICmicro MID-RANGE MCU FAMILY
9.1
DS31009A-page 9-2
Introduction
General purpose I/O pins can be considered the simplest of peripherals. They allow the
PICmicro™ to monitor and control other devices. To add flexibility and functionality to a device,
some pins are multiplexed with an alternate function(s). These functions depend on which
peripheral features are on the device. In general, when a peripheral is functioning, that pin may
not be used as a general purpose I/O pin.
For most ports, the I/O pin’s direction (input or output) is controlled by the data direction register,
called the TRIS register. TRIS<x> controls the direction of PORT<x>. A ‘1’ in the TRIS bit corre-
sponds to that pin being an input, while a ‘0’ corresponds to that pin being an output. An easy
way to remember is that a ‘1’ looks like an I (input) and a ‘0’ looks like an O (output).
The PORT register is the latch for the data to be output. When the PORT is read, the device reads
the levels present on the I/O pins (not the latch). This means that care should be taken with
read-modify-write commands on the ports and changing the direction of a pin from an input to an
output.
Figure 9-1
be multiplexed onto the I/O pin. Reading the PORT register reads the status of the pins whereas
writing to it will write to the port latch. All write operations (such as BSF and BCF instructions) 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.
Figure 9-1: Typical I/O Port
WR PORT
WR TRIS
RD PORT
Data bus
Note: I/O pin has protection diodes to V
shows a typical I/O port. This does not take into account peripheral functions that may
Data Latch
TRIS Latch
D
CK
D
CK
RD TRIS
Q
Q
Q
Q
DD
and V
Q
SS
EN
.
D
V
V
P
N
DD
SS
1997 Microchip Technology Inc.
Trigger
Schmitt
TTL or
I/O pin