PIC16F946T-I/PT Microchip Technology, PIC16F946T-I/PT Datasheet - Page 85

• Manufacturer Part Number: PIC16F946T-I/PT
• Description: Microcontroller
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F946T-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 14KB (8K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 336 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: 64-TFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MA160011 - DAUGHTER BOARD PICDEM LCD 16F91X
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

5.0
The Timer0 module timer/counter has the following
features:
• 8-bit timer/counter
• Readable and writable
• 8-bit software programmable prescaler
• Internal or external clock select
• Interrupt on overflow from FFh to 00h
• Edge select for external clock
Figure 5-1 is a block diagram of the Timer0 module and
the prescaler shared with the WDT.
5.1
Timer mode is selected by clearing the T0CS bit
(OPTION_REG<5>). In Timer mode, the Timer0
module will increment every instruction cycle (without
prescaler). If TMR0 is written, the increment is inhibited
for the following two instruction cycles. The user can
work around this by writing an adjusted value to the
TMR0 register.
FIGURE 5-1:
© 2005 Microchip Technology Inc.
T0CKI
SWDTEN
pin
WDTE
(= F
Note:
CLKO
OSC
INTOSC
T0SE
TIMER0 MODULE
Timer0 Operation
31 kHz
/4)
T0SE, T0CS, PSA and PS<2:0> are bits in the Option register; WDTPS<3:0> are bits in the WDTCON register.
Watchdog
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
Timer
T0CS
0
1
PSA
Prescaler
0
1
16-bit
16
Prescaler
WDTPS<3:0>
8-bit
Preliminary
8
PS<2:0>
Counter mode is selected by setting the T0CS bit
(OPTION_REG<5>). In this mode, the Timer0 module
will increment either on every rising or falling edge of pin
RA4/C1OUT/T0CKI/SEG4. The incrementing edge is
determined by the source edge (T0SE) control bit
(OPTION_REG<4>). Clearing the T0SE bit selects the
rising edge.
5.2
A Timer0 interrupt is generated when the TMR0
register timer/counter overflows from FFh to 00h. This
overflow sets the T0IF bit (INTCON<2>). The interrupt
can be masked by clearing the T0IE bit (INTCON<5>).
The T0IF bit must be cleared in software by the Timer0
module Interrupt Service Routine before re-enabling
this interrupt. The Timer0 interrupt cannot wake the
processor from Sleep, since the timer is shut off during
Sleep.
Timer0 Interrupt
PSA
PSA
1
0
1
0
SYNC 2
Cycles
Time-out
WDT
PIC16F946
Data Bus
Set Flag bit T0IF
DS41265A-page 83
8
TMR0
on Overflow