參數資料
型號: PIC16F785
廠商: Microchip Technology Inc.
英文描述: 20-Pin Flash-Based 8-Bit CMOS Microcontroller with Two-Phase Asychronous Feedback PWM, Dual High-Speed Comparators and Dual Operational Amplifiers
中文描述: 20引腳基于閃存的8兩相異步反饋的PWM,雙高位CMOS微控制器的高速比較器和雙運算放大器
文件頁數: 32/178頁
文件大?。?/td> 1620K
代理商: PIC16F785
PIC16F785
DS41249A-page 30
Preliminary
2004 Microchip Technology Inc.
FIGURE 3-7:
TWO-SPEED START-UP
3.7
Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) is designed to
allow the device to continue to operate in the event of
an oscillator failure. The FSCM can detect oscillator
failure at any point after the device has exited a Reset
or Sleep condition and the Oscillator Start-up Timer
(OST) has expired.
FIGURE 3-8:
FSCM BLOCK DIAGRAM
The FSCM function is enabled by setting the FCMEN
bit in Configuration Word (CONFIG). It is applicable to
all external clock options (LP, XT, HS, EC, RC or I/O
modes).
In the event of an external clock failure, the FSCM will
set the OSFIF bit (PIR1<2>) and generate an oscillator
fail interrupt if the OSFIE bit (PIE1<2>) is set. The
device will then switch the system clock to the internal
oscillator. The system clock will continue to come from
the internal oscillator unless the external clock recovers
and the Fail-Safe condition is exited.
The frequency of the internal oscillator will depend
upon the value contained in the IRCF bits
(OSCCON<6:4>).
Upon
condition,
the
OSTS
automatically cleared to reflect that the internal
oscillator is active and the WDT is cleared. The SCS bit
(OSCCON<0>) is not updated. Enabling FSCM does
not affect the LTS bit.
entering
bit
the
Fail-Safe
(OSCCON<3>)
is
The FSCM sample clock is generated by dividing the
LFINTOSC clock by 64. This will allow enough time
between FSCM sample clocks for a system clock edge
to occur. Figure 3-8 shows the FSCM block diagram.
On the rising edge of the sample clock, the monitoring
latch (CM =
0
) will be cleared. On a falling edge of the
primary system clock, the monitoring latch will be set
(CM =
1
). In the event that a falling edge of the sample
clock occurs, and the monitoring latch is not set, a clock
failure has been detected. The assigned internal
oscillator is enabled when FSCM is enabled as
reflected by the IRCF bits.
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
0
1
1022
1023
PC
PC + 1
PC + 2
OST
T
INTOSC
OSC1
OSC2
Program Counter
System Clock
Primary
Clock
LFINTOSC
Oscillator
÷ 64
S
C
Q
31 kHz
(~32 μs)
488 Hz
(~2 ms)
Clock Monitor
Latch (CM)
(edge-triggered)
Clock
Failure
Detected
Q
Note:
Two-Speed Start-up is automatically
enabled when the Fail-Safe Clock Monitor
mode is enabled.
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參數描述
PIC16F785-E/ML 功能描述:8位微控制器 -MCU 3.5 KB 128 RAM 18I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 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 安裝風格:SMD/SMT
PIC16F785-E/P 功能描述:8位微控制器 -MCU 14KB 368 RAM 33 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 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 安裝風格:SMD/SMT
PIC16F785-E/SO 功能描述:8位微控制器 -MCU 3.5KB FL 128R 18 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 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 安裝風格:SMD/SMT
PIC16F785-E/SS 功能描述:8位微控制器 -MCU 3.5KB FL 128R 18 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 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 安裝風格:SMD/SMT
PIC16F785-I/ML 功能描述:8位微控制器 -MCU 3.5 KB 128 RAM 18I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數據總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數據 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 安裝風格:SMD/SMT