PIC16F688-I/P Microchip Technology, PIC16F688-I/P Datasheet - Page 52

• Manufacturer Part Number: PIC16F688-I/P
• Description: IC PIC MCU FLASH 4KX14 14DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/P

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 14-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• 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
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 2
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Data Rom Size: 256 B
• Height: 3.3 mm
• Length: 19.05 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2 V
• Width: 6.35 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162066 - HEADER INTRFC MPLAB ICD2 20PINAC162061 - HEADER INTRFC MPLAB ICD2 20PINDM163029 - BOARD PICDEM FOR MECHATRONICSAC162056 - HEADER INTERFACE ICD2 16F688ACICE0207 - MPLABICE 14P 300 MIL ADAPTERAC124001 - MODULE SKT PROMATEII 8DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC16F688
6.1
Timer1 can operate in one of three modes:
• 16-bit timer with prescaler
• 16-bit synchronous counter
• 16-bit asynchronous counter
In Timer mode, Timer1 is incremented on every instruc-
tion cycle. In Counter mode, Timer1 is incremented on
the rising edge of the external clock input T1CKI. In
addition, the Counter mode clock can be synchronized
to
asynchronously.
In Counter and Timer modules, the counter/timer clock
can be gated by the Timer1 gate, which can be
selected as either the T1G pin or Comparator 2 output.
If an external clock oscillator is needed (and the
microcontroller is using the INTOSC without CLKOUT),
Timer1 can use the LP oscillator as a clock source.
6.2
The Timer1 register pair (TMR1H:TMR1L) increments
to FFFFh and rolls over to 0000h. When Timer1 rolls
over, the Timer1 interrupt flag bit (PIR1<0>) is set. To
enable the interrupt on rollover, you must set these bits:
• Timer1 Interrupt Enable bit (PIE1<0>)
• PEIE bit (INTCON<6>)
• GIE bit (INTCON<7>)
The interrupt is cleared by clearing the TMR1IF bit in
the Interrupt Service Routine.
FIGURE 6-2:
DS41203B-page 50
Note:
Note:
T1CKI = 1
when TMR1
Enabled
T1CKI = 0
when TMR1
Enabled
the
Note 1: Arrows indicate counter increments.
Timer1 Modes of Operation
Timer1 Interrupt
microcontroller
In Counter mode, a falling edge must be
registered by the counter prior to the first
incrementing rising edge.
The TMR1H:TTMR1L register pair and the
TMR1IF bit should be cleared before
enabling interrupts.
2: In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of
the clock.
TIMER1 INCREMENTING EDGE
system
clock
or
Preliminary
run
6.3
Timer1 has four prescaler options allowing 1, 2, 4 or 8
divisions of the clock input. The T1CKPS bits
(T1CON<5:4>) control the prescale counter. The
prescale counter is not directly readable or writable;
however, the prescaler counter is cleared upon a write
to TMR1H or TMR1L.
6.4
Timer1 gate source is software configurable to be the
T1G pin or the output of Comparator 2. This allows the
device to directly time external events using T1G or
analog events using Comparator 2. See CMCON1
(Register 7-2) for selecting the Timer1 gate source.
This feature can simplify the software for a Delta-Sigma
A/D converter and many other applications. For more
information on Delta-Sigma A/D converters, see the
Microchip web site (www.microchip.com).
Timer1 gate can be inverted using the T1GINV bit
(T1CON<7>), whether it originates from the T1G pin or
Comparator 2 output. This configures Timer1 to
measure either the active-high or active-low time
between events.
Note:
Timer1 Prescaler
Timer1 Gate
TMR1GE bit (T1CON<6>) must be set to
use either T1G or C2OUT as the Timer1
gate source. See Register 7-2 for more
information on selecting the Timer1 gate
source.
 2004 Microchip Technology Inc.