- 您現在的位置：買賣IC網 > PDF目錄363901 > W79E804A (WINBOND ELECTRONICS CORP) 8-BIT MICROCONTROLLER PDF資料下載
參數資料
| 型號： | W79E804A |
| 廠商： | WINBOND ELECTRONICS CORP |
| 元件分類： | 8位微控制器 |
| 英文描述： | 8-BIT MICROCONTROLLER |
| 中文描述： | 8位微控制器 |
| 文件頁數： | 57/115頁 |
| 文件大小： | 1456K |
| 代理商： | W79E804A |
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頁當前第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
W79E804A/803A/802A
Publication Release Date: July 16, 2007
- 57 -
Revision A2
11. RESET CONDITIONS
The user has several hardware related options for placing the W79E804 series into reset condition. In
general, most register bits go to their reset value irrespective of the reset condition, but there are a few
flags whose state depends on the source of reset. The user can use these flags to determine the
cause of reset using software.
11.1 Sources of reset
11.1.1 External Reset
The device samples the /RST pin every machine cycle during state C4. The /RST pin must be held
low for at least two machine cycles before the reset circuitry applies an internal reset signal. Thus, this
reset is a synchronous operation and requires the clock to be running.
The device remains in the reset state as long as /RST is low and remains low up to two machine
cycles after /RST is deactivated. Then, the device begins program execution at 0000h. There are no
flags associated with the external reset, but, since the other two reset sources do have flags, the
external reset is the cause if those flags are clear.
11.1.2 Power-On Reset (POR)
If the power supply falls below V
rst
, the device goes into the reset state. When the power supply
returns to proper levels, the device performs a power-on reset and sets the POR flag. The software
should clear the POR flag, or it will be difficult to determine the source of future resets.
11.1.3 Watchdog Timer Reset
The Watchdog Timer is a free-running timer with programmable time-out intervals. The program must
clear the Watchdog Timer before the time-out interval is reached to restart the count. If the time-out
interval is reached, an interrupt flag is set. 512 clocks later, if the Watchdog Reset is enabled and the
Watchdog Timer has not been cleared, the Watchdog Timer generates a reset. The reset condition is
maintained by the hardware for two machine cycles, and the WTRF bit in WDCON is set. Afterwards,
the device begins program execution at 0000h.
11.2 Reset State
When the device is reset, most registers return to their initial state. The Watchdog Timer is disabled if
the reset source was a power-on reset. The port registers are set to FFh, which puts most of the port
pins in a high state. The Program Counter is set to 0000h, and the stack pointer is reset to 07h. After
this, the device remains in the reset state as long as the reset conditions are satisfied.
Reset does not affect the on-chip RAM, however, so RAM is preserved as long as VDD remains
above approximately 2 V, the minimum operating voltage for the RAM. If VDD falls below 2 V, the
RAM contents are also lost. In either case, the stack pointer is always reset, so the stack contents are
lost.
相關PDF資料 |
PDF描述 |
|---|---|
| W79E804ADG | 8-BIT MICROCONTROLLER |
| W79E804ASG | 8-BIT MICROCONTROLLER |
| W80NF06 | N-CHANNEL 60V - 0.0065OHM - 80A TO-220/D2PAK/TO-247 STripFET II POWER MOSFET |
| W81181AD | USB HUB CONTROLLER |
| W81181D | USB HUB CONTROLLER |
相關代理商/技術參數 |
參數描述 |
|---|---|
| W79E804ADG | 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER |
| W79E804ASG | 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER |
| W79E8213 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:W79E8213中文資料 |
| W79E8213_W79E8213R | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Table of contents- |
| W79E8213AKG | 制造商:Nuvoton Technology Corp 功能描述:IC MCU 8BIT 4K FLASH 20DIP |
發布緊急采購，3分鐘左右您將得到回復。