參數(shù)資料
型號： PIC16F871T-E/L
廠商： Microchip Technology
文件頁數(shù)： 138/143頁
文件大小： 0K
描述： IC MCU CMOS 20MHZ 2K FLSH 44PLCC
標(biāo)準(zhǔn)包裝： 500
系列： PIC® 16F
核心處理器： PIC
芯體尺寸： 8-位
速度： 20MHz
連通性： UART/USART
外圍設(shè)備： 欠壓檢測/復(fù)位，POR，PWM，WDT
輸入/輸出數(shù)： 33
程序存儲器容量： 3.5KB（2K x 14）
程序存儲器類型： 閃存
EEPROM 大?。?/td> 64 x 8
RAM 容量： 128 x 8
電壓 - 電源 (Vcc/Vdd)： 4 V ~ 5.5 V
數(shù)據(jù)轉(zhuǎn)換器： A/D 8x10b
振蕩器型： 外部
工作溫度： -40°C ~ 125°C
封裝/外殼： 44-LCC（J 形引線）
包裝： 帶卷 (TR)
PIC16F870/871
DS30569B-page 92
2003 Microchip Technology Inc.
11.4
Power-on Reset (POR)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected (in the range of 1.2V - 1.7V). To
take advantage of the POR, tie the MCLR pin directly
(or through a resistor) to VDD. This will eliminate
external RC components usually needed to create a
Power-on Reset. A maximum rise time for VDD is
specified. See Electrical Specifications for details.
When the device starts normal operation (exits the
RESET condition), device operating parameters (volt-
age, frequency, temperature,...) must be met to ensure
operation. If these conditions are not met, the device
must be held in RESET until the operating conditions
are met. Brown-out Reset may be used to meet the
start-up conditions. For additional information, refer to
Application Note, AN007, “Power-up Trouble Shooting”
(DS00007).
11.5
Power-up Timer (PWRT)
The Power-up Timer provides a fixed 72 ms nominal
time-out on power-up only from the POR. The Power-
up Timer operates on an internal RC oscillator. The
chip is kept in RESET as long as the PWRT is active.
The PWRT’s time delay allows VDD to rise to an
acceptable level. A configuration bit is provided to
enable/disable the PWRT.
The power-up time delay will vary from chip to chip due
to VDD, temperature and process variation. See DC
parameters for details (TPWRT, parameter #33).
11.6
Oscillator Start-up Timer (OST)
The Oscillator Start-up Timer (OST) provides a delay of
1024 oscillator cycles (from OSC1 input) after the
PWRT delay is over (if PWRT is enabled). This helps to
ensure that the crystal oscillator or resonator has
started and stabilized.
The OST time-out is invoked only for XT, LP and HS
modes and only on Power-on Reset or Wake-up from
SLEEP.
11.7
Brown-out Reset (BOR)
The configuration bit, BOREN, can enable or disable
the Brown-out Reset circuit. If VDD falls below VBOR
(parameter D005, about 4V) for longer than TBOR
(parameter #35, about 100
S), the brown-out situation
will reset the device. If VDD falls below VBOR for less
than TBOR, a RESET may not occur.
Once the brown-out occurs, the device will remain in
Brown-out Reset until VDD rises above VBOR. The
Power-up Timer then keeps the device in RESET for
TPWRT (parameter #33, about 72 ms). If VDD should fall
below VBOR during TPWRT, the Brown-out Reset pro-
cess will restart when VDD rises above VBOR with the
Power-up Timer Reset. The Power-up Timer is always
enabled when the Brown-out Reset circuit is enabled,
regardless of the state of the PWRT configuration bit.
11.8
Time-out Sequence
On power-up, the time-out sequence is as follows: The
PWRT delay starts (if enabled) when a POR Reset
occurs. Then OST starts counting 1024 oscillator
cycles when PWRT ends (LP, XT, HS). When the OST
ends, the device comes out of RESET.
If MCLR is kept low long enough, the time-outs will
expire. Bringing MCLR high will begin execution imme-
diately. This is useful for testing purposes or to synchro-
nize more than one PIC16F870/871 device operating in
parallel.
Table 11-5 shows the RESET conditions for the
STATUS, PCON and PC registers, while Table 11-6
shows the RESET conditions for all the registers.
11.9
Power Control/Status Register
(PCON)
The Power Control/Status Register, PCON, has up to
two bits depending upon the device.
Bit0 is Brown-out Reset Status bit, BOR. Bit BOR is
unknown on a Power-on Reset. It must then be set by
the user and checked on subsequent RESETS to see if
bit BOR cleared, indicating a BOR occurred. When the
Brown-out Reset is disabled, the state of the BOR bit is
unpredictable and is, therefore, not valid at any time.
Bit1 is POR (Power-on Reset Status bit). It is cleared on
a Power-on Reset and unaffected otherwise. The user
must set this bit following a Power-on Reset.
TABLE 11-3:
TIME-OUT IN VARIOUS SITUATIONS
Oscillator
Configuration
Power-up
Brown-out
Wake-up from SLEEP
PWRTEN = 0
PWRTEN = 1
XT, HS, LP
72 ms + 1024 TOSC
1024 TOSC
72 ms + 1024 TOSC
1024 TOSC
RC
72 ms
—
72 ms
—
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PIC16F871T-I/L 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 33 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
PIC16F871T-I/PT 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 33 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
PIC16F872-E/SO 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 22 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
PIC16F872-E/SOVAO 制造商:Microchip Technology Inc 功能描述:
PIC16F872-E/SP 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 22 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
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