- 您現(xiàn)在的位置：買賣IC網 > PDF目錄381451 > AT43USB326-AC (ATMEL CORP) Multimedia USB Keyboard Controller with Embedded Hub PDF資料下載
參數資料
| 型號： | AT43USB326-AC |
| 廠商： | ATMEL CORP |
| 元件分類： | 微控制器/微處理器 |
| 英文描述： | Multimedia USB Keyboard Controller with Embedded Hub |
| 中文描述： | 8-BIT, MROM, 12 MHz, RISC MICROCONTROLLER, PQFP48 |
| 封裝： | 7 X 7 MM, 1.40 MM THICKNESS, 0.50 MM PITCH, PLASTIC, MS-026BBC, LQFP-48 |
| 文件頁數： | 98/102頁 |
| 文件大?。?/td> | 511K |
| 代理商： | AT43USB326-AC |
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頁當前第98頁第99頁第100頁第101頁第102頁
98
AT43USB326
3313D–USB–04/06
Errata Sheet
Errata (All Date Codes): Missed Watchdog Timer Reset
Problem
There is a synchronization problem between the watchdog clock and the AVR clock. Even
though the clock inputs to both the watchdog timer and the AVR core are generated through
the same crystal, the two clock sources are not going through the same PLL. The AVR is
clocked at 12 MHz and the watchdog timer is clocked at 1MHz. The WDR (Watchdog Reset)
instruction is a one-clock-cycle instruction. As such, when a watchdog timer reset occurs due
to a WDR, the watchdog timer may miss the reset. This happens frequently if the AVR is
clocked much faster than the watchdog timer.
Fix/Workaround
A workaround is to invoke the WDR repetitively to ensure that the watchdog timer will be able
to receive the reset signal. If the AVR runs at 12 MHz, the WDR command must be invoked
fourteen times back to back.
The following is the sample code for resetting and arming the watchdog timer, assuming the
AVR is running at 12 MHz:
asm ( "ldi r16,15\n WDR\n WDR\n WDR\n WDR\n WDR\n WDR\n WDR\n WDR\n WDR\n
WDR\n WDR\n WDR\n WDR\n out 0x21,r16 " );
To disarm and disable the watchdog, do the following:
asm ( "ldi r16,0x18\nldi r17,0x10\n\n out 0x21,r16\n out 0x21,r17 " );
Please note that if the AVR runs at 24 MHz, the WDR should be invoked twenty-six times.
相關PDF資料 |
PDF描述 |
|---|---|
| AT43USB326-AU | Multimedia USB Keyboard Controller with Embedded Hub |
| AT43USB351M-AC | Full-speed/Low-speed USB Microcontroller with ADC and PWM |
| AT43USB353M-AC | Low Cost Full-speed USB Microcontroller with Embedded Hub, ADC and PWM |
| AT43USB355E-AC | Full-speed USB Microcontroller with Embedded Hub, ADC and PWM |
| AT43USB355E-AU | Full-speed USB Microcontroller with Embedded Hub, ADC and PWM |
相關代理商/技術參數 |
參數描述 |
|---|---|
| AT43USB326-AU | 功能描述:USB 接口集成電路 USB KEYBOARD FOR LOGITECH - IND TEMP RoHS:否 制造商:Cypress Semiconductor 產品:USB 2.0 數據速率: 接口類型:SPI 工作電源電壓:3.15 V to 3.45 V 工作電源電流: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:WLCSP-20 |
| AT43USB351M | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Missed Watchdog Timer Reset |
| AT43USB351M_04 | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Full-speed/ Low-speed USB Microcontroller with ADC and PWM |
| AT43USB351M-AC | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Full-speed/ Low-speed USB Microcontroller with ADC and PWM |
| AT43USB353M | 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Missed Watchdog Timer Reset |
發(fā)布緊急采購，3分鐘左右您將得到回復。