- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄98076 > SAH-C515A-4R (INFINEON TECHNOLOGIES AG) 8-BIT, MROM, 24 MHz, MICROCONTROLLER, PQFP80 PDF資料下載
參數(shù)資料
| 型號： | SAH-C515A-4R |
| 廠商： | INFINEON TECHNOLOGIES AG |
| 元件分類： | 微控制器/微處理器 |
| 英文描述： | 8-BIT, MROM, 24 MHz, MICROCONTROLLER, PQFP80 |
| 封裝： | METRIC, PLASTIC, QFP-80 |
| 文件頁數(shù)： | 123/182頁 |
| 文件大?。?/td> | 1917K |
| 代理商： | SAH-C515A-4R |
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頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁當(dāng)前第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁第142頁第143頁第144頁第145頁第146頁第147頁第148頁第149頁第150頁第151頁第152頁第153頁第154頁第155頁第156頁第157頁第158頁第159頁第160頁第161頁第162頁第163頁第164頁第165頁第166頁第167頁第168頁第169頁第170頁第171頁第172頁第173頁第174頁第175頁第176頁第177頁第178頁第179頁第180頁第181頁第182頁
Semiconductor Group
5-3
1997-08-01
Reset / System Clock
C515A
5.2
Fast Internal Reset after Power-On
The C515A uses the oscillator watchdog unit for a fast internal reset procedure after power-on.
Figure 5-1 shows the power-on sequence under control of the oscillator watchdog.
Normally the devices of the 8051 family do not enter their default reset states before the on-chip
oscillator starts. The reason is that the external reset signal must be internally synchronized and
processed in order to bring the device into the correct reset state. Especially if a crystal is used the
start up time of the oscillator is relatively long (typ. 10 ms). During this time period the pins have an
undefined state which could have severe effects especially to actuators connected to port pins.
In the C515A the oscillator watchdog unit avoids this situation. In this case, after power-on the
oscillator watchdog's RC oscillator starts working within a very short start-up time (typ. less than 2
microseconds). In the following the watchdog circuitry detects a failure condition for the on-chip
oscillator because this has not yet started (a failure is always recognized if the watchdog's RC
oscillator runs faster than the on-chip oscillator). As long as this condition is detected the watchdog
uses the RC oscillator output as clock source for the chip rather than the on-chip oscillator's output.
This allows correct resetting of the part and brings also all ports to the defined state (see figure 5-7).
Under worst case conditions (fast
V
CC rise time - e.g. 1s, measured from VCC = 4.25 V up to stable
port condition), the delay between power-on and the correct port reset state is :
– Typ.:
18
s
– Max.:
34
s
The RC oscillator will already run at a
V
CC below 4.25V (lower specification limit). Therefore, at
slower
V
CC rise times the delay time will be less than the two values given above.
After the on-chip oscillator has finally started, the oscillator watchdog detects the correct function;
then the watchdog still holds the reset active for a time period of max. 768 cycles of the RC oscillator
clock in order to allow the oscillation of the on-chip oscillator to stabilize (figure 5-7, II).
Subsequently the clock is supplied by the on-chip oscillator and the oscillator watchdog's reset
request is released (figure 5-7, III). However, an externally applied reset still remains active (figure
5-7, IV) and the device does not start program execution (figure 5-7, V) before the external reset is
also released.
Although the oscillator watchdog provides a fast internal reset it is additionally necessary to apply
the external reset signal when powering up. The reasons are as follows:
–
Termination of software power down mode
–
Reset of the status flag OWDS that is set by the oscillator watchdog during the power up
sequence.
Using a crystal or ceramic resonator for clock generation, the external reset signal must be held
active at least until the on-chip oscillator has started and the internal watchdog reset phase is
completed (after phase III in figure 5-7). When an external clock generator is used, phase II is very
short. Therefore, an external reset time of typically 1 ms is sufficent in most applications.
Generally, for reset time generation at power-on an external capacitor can be applied to the RESET
pin.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SAH-C515C-LM | 8-BIT, 10 MHz, MICROCONTROLLER, PQFP80 |
| SAH-XC2210U-8F66R | 32-BIT, FLASH, 66 MHz, RISC MICROCONTROLLER, PDSO38 |
| SAH-XC2387A-104F80L | 16-BIT, FLASH, 80 MHz, RISC MICROCONTROLLER, PQFP144 |
| SAH-XC2387C-200F100L | 32-BIT, FLASH, 100 MHz, RISC MICROCONTROLLER, PQFP144 |
| SAH-XC2387C-136F100L | 32-BIT, FLASH, 100 MHz, RISC MICROCONTROLLER, PQFP144 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SAH-C517A | 制造商:INFINEON 制造商全稱:Infineon Technologies AG 功能描述:8-bit CMOS MICROCONTROLLER |
| SAHC684M50R501 | 制造商:SHARMA 制造商全稱:Sharma Electro Components,Inc 功能描述:Tantalum Capacitors |
| SAHC685M20R501 | 制造商:SHARMA 制造商全稱:Sharma Electro Components,Inc 功能描述:Tantalum Capacitors |
| SAHD106M25R501 | 制造商:SHARMA 制造商全稱:Sharma Electro Components,Inc 功能描述:Tantalum Capacitors |
| SAHD155M50R501 | 制造商:SHARMA 制造商全稱:Sharma Electro Components,Inc 功能描述:Tantalum Capacitors |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。