- 您現(xiàn)在的位置：買賣IC網 > PDF目錄3895 > PIC16F57-I/SS (Microchip Technology)IC MCU FLASH 2KX12 28SSOP PDF資料下載
參數(shù)資料
| 型號： | PIC16F57-I/SS |
| 廠商： | Microchip Technology |
| 文件頁數(shù)： | 31/88頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC MCU FLASH 2KX12 28SSOP |
| 產品培訓模塊： | Asynchronous Stimulus 8-bit PIC® Microcontroller Portfolio |
| 標準包裝： | 47 |
| 系列： | PIC® 16F |
| 核心處理器： | PIC |
| 芯體尺寸： | 8-位 |
| 速度： | 20MHz |
| 外圍設備： | POR，WDT |
| 輸入/輸出數(shù)： | 20 |
| 程序存儲器容量： | 3KB（2K x 12） |
| 程序存儲器類型： | 閃存 |
| RAM 容量： | 72 x 8 |
| 電壓 - 電源 (Vcc/Vdd)： | 2 V ~ 5.5 V |
| 振蕩器型： | 外部 |
| 工作溫度： | -40°C ~ 85°C |
| 封裝/外殼： | 28-SSOP（0.209"，5.30mm 寬） |
| 包裝： | 管件 |
| 產品目錄頁面： | 638 (CN2011-ZH PDF) |
| 配用： | AC164307-ND - MODULE SKT FOR PM3 28SSOP AC164014-ND - MODULE SKT PROMATEII 44PQFP |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁當前第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁
2007 Microchip Technology Inc.
DS41213D-page 35
PIC16F5X
7.1
Using Timer0 with an External
Clock
When an external clock input is used for Timer0, it must
meet
certain
requirements.
The
external
clock
requirement is due to internal phase clock (TOSC)
synchronization. Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
7.1.1
EXTERNAL CLOCK
SYNCHRONIZATION
When no prescaler is used, the external clock is the
Timer0 input. The synchronization of T0CKI with the
internal phase clocks is accomplished by sampling the
prescaler output on the Q2 and Q4 cycles of the inter-
nal phase clocks (Figure 7-4). Therefore, it is neces-
sary for T0CKI to be high for at least 2TOSC (and a small
RC delay of 20 ns) and low for at least 2TOSC (and a
small RC delay of 20 ns). Refer to the electrical
specification of the desired device.
When a prescaler is used, the external clock input is
divided by the asynchronous ripple counter-type
prescaler so that the prescaler output is symmetrical.
For the external clock to meet the sampling require-
ment, the ripple counter must be taken into account.
Therefore, it is necessary for T0CKI to have a period of
at least 4TOSC (and a small RC delay of 40 ns) divided
by the prescaler value. The only requirement on T0CKI
high and low time is that they do not violate the
minimum pulse width requirement of 10 ns. Refer to
parameters 40, 41 and 42 in the electrical specification
of the desired device.
7.1.2
TIMER0 INCREMENT DELAY
Since the prescaler output is synchronized with the
internal clocks, there is a small delay from the time the
external clock edge occurs to the time the Timer0
module is actually incremented. Figure 7-4 shows the
delay from the external clock edge to the timer
incrementing.
FIGURE 7-4:
TIMER0 TIMING WITH EXTERNAL CLOCK
7.2
Prescaler
An 8-bit counter is available as a prescaler for the
Timer0 module, or as a postscaler for the Watchdog
Timer
(WDT),
respectively
Period”). For simplicity, this counter is being referred
to as “prescaler” throughout this data sheet. Note that
the prescaler may be used by either the Timer0 module
or the WDT, but not both. Thus, a prescaler assignment
for the Timer0 module means that there is no prescaler
for the WDT, and vice-versa.
The PSA and PS<2:0> bits (OPTION<3:0>) determine
prescaler assignment and prescale ratio.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF 1, MOVWF 1,
BSF 1
, x, etc.) will clear the prescaler. When assigned
to WDT, a CLRWDT instruction will clear the prescaler
along with the WDT. The prescaler is neither readable
nor writable. On a Reset, the prescaler contains all ‘0’s.
Increment Timer0 (Q4)
External Clock Input or
Q1
Q2
Q3 Q4
Q1
Q2
Q3 Q4
Q1
Q2
Q3 Q4
Q1
Q2
Q3 Q4
Timer0
T0
T0 + 1
T0 + 2
Small pulse
misses sampling
External Clock/Prescaler
Output After Sampling
(2)
Prescaler Output(1)
(3)
Note
1:
External clock if no prescaler selected; prescaler output otherwise.
2:
The arrows indicate the points in time where sampling occurs.
3:
Delay from clock input change to Timer0 increment is 3TOSC to 7TOSC (duration of Q = TOSC). Therefore, the error
in measuring the interval between two edges on Timer0 input =
± 4TOSC max.
相關PDF資料 |
PDF描述 |
|---|---|
| PIC12F510-I/MS | IC PIC MCU FLASH 1.5KB 8MSOP |
| PIC12F519-I/MS | IC PIC MCU FLASH 1KX12 8MSOP |
| PIC12F629T-E/SN | IC MCU CMOS 8BIT 1K FLASH 8-SOIC |
| PIC12F675T-I/SN | IC MCU CMOS 1K FLASH W/AD 8-SOIC |
| PIC12F509-I/SM | IC PIC MCU FLASH 1KX12 8-SOIJ |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| PIC16F57T-E/SO | 功能描述:8位微控制器 -MCU 3KB 72 RAM 20 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)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(shù)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 |
| PIC16F57T-E/SS | 功能描述:8位微控制器 -MCU 3KB 72 RAM 20 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)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(shù)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 |
| PIC16F57T-I/ML | 制造商:Microchip Technology Inc 功能描述:28 PIN, 3KB STD FLASH, 72 RAM, 20 I/O - Tape and Reel |
| PIC16F57T-I/SO | 功能描述:8位微控制器 -MCU 3KB 72 RAM 20 I/O RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)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(shù)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 |
| PIC16F57T-I/SO-CUT TAPE | 制造商:Microchip 功能描述:PIC16 Series 72 B RAM 3 kB Flash 8-Bit CMOS Microcontroller - SOIC-28 |
發(fā)布緊急采購，3分鐘左右您將得到回復。