PIC16HV785 Microchip Technology Inc., PIC16HV785 Datasheet - Page 51

• Manufacturer Part Number: PIC16HV785
• Description: 20-pin Flash-based 8-bit Cmos Microcontroller
• Manufacturer: Microchip Technology Inc.

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:
© 2006 Microchip Technology Inc.
RA2/AN2/T0CKI/INT/C1OUT
Note:
Note 1: T0SE, T0CS, PSA, PS<2:0> are bits in the OPTION_REG (see Register 2-2).
SWDTEN
WDTE
(= F
CLKOUT
T0SE
OSC
31 kHz
INTRC
2: WDTPS<3:0> are bits in the WDTCON register (see Register 15-2).
TIMER0 MODULE
Timer0 Operation
/4)
Additional information on the Timer0
module is available in the “PICmicro
Range MCU Family Reference Manual”
(DS33023).
(1)
Watchdog
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
Timer
T0CS
0
1
(1)
PSA
Prescaler
0
1
16-bit
(1)
WDTPS<3:0>
16
®
Prescaler
Mid-
8-bit
Preliminary
8
PS<0:2>
(2)
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 RA2/AN2/T0CKI/INT/C1OUT. 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.
(1)
Note 1: Counter mode has specific external clock
PIC16F785/HV785
2: The ANSEL0 (91h) register must be ini-
Timer0 Interrupt
PSA
PSA
requirements. Additional information on
these requirements is available in the
“PICmicro
erence Manual” (DS33023).
tialized to configure an analog channel as
a digital input. Pins configured as analog
inputs will read ‘0’.
1
0
1
0
(1)
(1)
SYNC 2
Cycles
Time-out
®
WDT
Mid-Range MCU Family Ref-
Data Bus
Set Flag bit T0IF
DS41249D-page 49
8
TMR0
on Overflow