PIC16F721-I/SO Microchip Technology, PIC16F721-I/SO Datasheet - Page 91

• Manufacturer Part Number: PIC16F721-I/SO
• Description: MCU PIC 4K FLASH 20-SOIC
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F721-I/SO

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Core Processor: PIC
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Number Of I /o: 17
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 12x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SOIC (0.300", 7.50mm Width)
• Controller Family/series: PIC16F
• No. Of I/o's: 18
• Ram Memory Size: 256Byte
• Cpu Speed: 16MHz
• No. Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

12.0
The Timer0 module is an 8-bit timer/counter with the
following features:
• 8-bit timer/counter register (TMR0)
• 8-bit prescaler (shared with Watchdog Timer)
• Programmable internal or external clock source
• Programmable external clock edge selection
• Interrupt on overflow
• TMR0 can be used to gate Timer1
Figure 12-1
12.1
The Timer0 module can be used as either an 8-bit timer
or an 8-bit counter.
FIGURE 12-1:
 2010 Microchip Technology Inc.
WDTE
T1GSS = 11
TMR1GE
T0CKI
F
OSC
TIMER0 MODULE
Timer0 Operation
/4
is a block diagram of the Timer0 module.
T0SE
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
Low-Power
WDT OSC
T0CS
0
1
Divide by
512
PSA
0
1
Prescaler
8-bit
8
PS<2:0>
12.1.1
The Timer0 module will increment every instruction
cycle, if used without a prescaler. 8-Bit Timer mode is
selected by clearing the T0CS bit of the OPTION
register.
When TMR0 is written, the increment is inhibited for
two instruction cycles immediately following the write.
12.1.2
In 8-Bit Counter mode, the Timer0 module will increment
on every rising or falling edge of the T0CKI pin.
8-Bit Counter mode using the T0CKI pin is selected by
setting the T0CS bit in the OPTION register to ‘1’.
The rising or falling transition of the incrementing edge
for either input source is determined by the T0SE bit in
the OPTION register.
Note:
PIC16F/LF720/721
8-BIT TIMER MODE
The value written to the TMR0 register
can be adjusted, in order to account for
the two instruction cycle delay when
TMR0 is written.
8-BIT COUNTER MODE
PSA
PSA
1
0
1
0
Time-out
2 T
S
WDT
YNC
CY
Set Flag bit T0IF
Overflow to Timer1
on Overflow
DS41430A-page 91
Data Bus
8
TMR0