參數(shù)資料
型號: pic12ce674
廠商: Microchip Technology Inc.
英文描述: 8-Pin, 8-Bit CMOS Microcontroller with A/D Converter(具A/D轉(zhuǎn)換器和EEPROM數(shù)據(jù)存儲器的8位微控制器)
中文描述: 8引腳,8位CMOS微控制器與A / D轉(zhuǎn)換器(具的A / D轉(zhuǎn)換器和EEPROM的數(shù)據(jù)存儲器的8位微控制器)
文件頁數(shù): 50/112頁
文件大?。?/td> 1205K
代理商: PIC12CE674
PIC12CE67X
DS40181A-page 50
Preliminary
1998 Microchip Technology Inc.
9.4
Power-on Reset (POR), Power-up
Timer (PWRT) and Oscillator Start-up
Timer (OST)
9.4.1
POWER-ON RESET (POR)
A Power-on Reset pulse is generated on-chip when
V
DD
rise is detected (in the range of 1.5V - 2.1V). To
take advantage of the POR, just tie the MCLR pin
directly (or through a resistor) to V
DD
. This will eliminate
external RC components usually needed to create a
Power-on Reset. A maximum rise time for V
DD
is spec-
ified. See Electrical Specifications for details.
When the device starts normal operation (exits the
reset condition), device operating parameters (voltage,
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.
For additional information, refer to Application Note
AN607, "Power-up Trouble Shooting"
9.4.2
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 V
DD
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 V
DD
, temperature, and process variation. See DC
parameters for details.
9.4.3
OSCILLATOR START-UP TIMER (OST)
The Oscillator Start-up Timer (OST) provides 1024
oscillator cycle (from OSC1 input) delay after the
PWRT delay is over. This ensures that the crystal oscil-
lator 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.
9.4.4
TIME-OUT SEQUENCE
On power-up the time-out sequence is as follows: First
PWRT time-out is invoked after the POR time delay has
expired. Then OST is activated. The total time-out will
vary based on oscillator configuration and the status of
the PWRT. For example, in RC mode with the PWRT
disabled, there will be no time-out at all. Figure 9-8,
Figure 9-9, and Figure 9-10 depict time-out sequences
on power-up.
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, the time-outs will expire. Then
bringing MCLR high will begin execution immediately
(Figure 9-9). This is useful for testing purposes or to
synchronize more than one PIC12CE67X device oper-
ating in parallel.
Table 9-5 shows the reset conditions for all the regis-
ters.
9.4.5
POWER CONTROL/STATUS REGISTER
(PCON)
The power control/status register, PCON (address
8Eh) has one bit. See Figure 4-8 for register.
Bit1 is POR (Power-on Reset). It is cleared on a Power-
on Reset and is unaffected otherwise. The user set this
bit following a Power-on Reset. On subsequent resets
if POR is ‘0’, it will indicate that a Power-on Reset must
have occurred.
TABLE 9-3:
TIME-OUT IN VARIOUS SITUATIONS
TABLE 9-4:
STATUS BITS AND THEIR SIGNIFICANCE
Oscillator Configuration
Power-up
Wake-up from SLEEP
PWRTE = 0
72 ms + 1024T
OSC
72 ms
PWRTE = 1
1024T
OSC
XT, HS, LP
INTRC, EXTRC
1024T
OSC
POR
TO
PD
0
0
0
1
1
1
1
1
0
x
0
0
u
1
1
x
0
1
0
u
0
Power-on Reset
Illegal, TO is set on POR
Illegal, PD is set on POR
WDT Reset
WDT Wake-up
MCLR Reset during normal operation
MCLR Reset during SLEEP or interrupt wake-up from SLEEP
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PIC12CE674-04/JM 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:8-Pin, 8-Bit CMOS Microcontroller with A/D Converter
PIC12CE674-04/JW 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:8-Pin, 8-Bit CMOS Microcontroller with A/D Converter and EEPROM Data Memory
PIC12CE674-04/P 功能描述:8位微控制器 -MCU 3.5KB 128 RAM 6 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
PIC12CE674-04/P 制造商:Microchip Technology Inc 功能描述:IC 8BIT CMOS MCU 12CE674 DIP8