參數(shù)資料
型號: PIC16F819
廠商: Microchip Technology Inc.
英文描述: 18/20-Pin Enhanced FLASH Microcontrollers with nanoWatt Technology(18/20引腳,納瓦技術(shù)增強FLASH微控制器)
中文描述: 18/20-Pin增強型閃存微控制器采用納瓦技術(shù)(18/20引腳,納瓦技術(shù)增強閃存微控制器)
文件頁數(shù): 55/164頁
文件大小: 3045K
代理商: PIC16F819
2002 Microchip Technology Inc.
Preliminary
DS39598C-page 53
PIC16F818/819
6.0
TIMER0 MODULE
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
Additional information on the Timer0 module is
available in the PICmicro Mid-Range MCU Family
Reference Manual (DS33023).
Figure 6-1 is a block diagram of the Timer0 module and
the prescaler shared with the WDT.
6.1
Timer0 Operation
Timer0 operation is controlled through the OPTION
register (see Register 2-2). Timer mode is selected by
clearing bit T0CS (OPTION<5>). In Timer mode, the
Timer0 module will increment every instruction cycle
(without prescaler). If the TMR0 register 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.
Counter mode is selected by setting bit T0CS
(OPTION<5>). In Counter mode, Timer0 will incre-
ment, either on every rising or falling edge of pin RA4/
T0CKI. The incrementing edge is determined by the
Timer0 Source Edge Select bit T0SE (OPTION<4>).
Clearing bit T0SE selects the rising edge. Restrictions
on the external clock input are discussed in detail in
Section 6.3.
The prescaler is mutually exclusively shared between
the Timer0 module and the Watchdog Timer. The pres-
caler is not readable or writable. Section 6.4 details the
operation of the prescaler.
6.2
Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0 reg-
ister overflows from FFh to 00h. This overflow sets bit
TMR0IF (INTCON<2>). The interrupt can be masked
by clearing bit TMR0IE (INTCON<5>). Bit TMR0IF
must be cleared in software by the Timer0 module
Interrupt Service Routine, before re-enabling this inter-
rupt. The TMR0 interrupt cannot awaken the processor
from SLEEP, since the timer is shut-off during SLEEP.
FIGURE 6-1:
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER
RA4/T0CKI
pin
T0SE
M
U
X
CLKO (= F
OSC
/4)
SYNC
2
Cycles
TMR0 reg
8-bit Prescaler
8 - to - 1MUX
M
U
X
M U X
31.25 kHz
WDT Timer
PSA
0
1
0
1
WDT
Time-out
PS2:PS0
8
Note:
T0CS, T0SE, PSA, PS2:PS0 are (OPTION<5:0>).
PSA
WDT Enable bit
M
U
X
0
1
0
1
Data Bus
Set Flag bit TMR0IF
on Overflow
8
PSA
T0CS
PRESCALER
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PIC16F819-E/P 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/SO 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/SS 功能描述:8位微控制器 -MCU 3.5KB 256 RAM 16 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
PIC16F819-E/SSVAO 制造商:Microchip Technology Inc 功能描述: