參數(shù)資料
型號: AT90USB1287
廠商: Atmel Corp.
英文描述: 8-bit Microcontroller with 64/128K Bytes of ISP Flash and USB Controller
中文描述: 8位64/128K的ISP字節(jié)閃存和控制器的USB微控制器
文件頁數(shù): 48/132頁
文件大小: 10886K
代理商: AT90USB1287
214
ATmega8535(L)
2502K–AVR–10/06
If differential channels are used, the selected reference should not be closer to AVCC
ADC Noise Canceler
The ADC features a noise canceler that enables conversion during sleep mode to
reduce noise induced from the CPU core and other I/O peripherals. The noise canceler
can be used with ADC Noise Reduction and Idle mode. To make use of this feature, the
following procedure should be used:
1.
Make sure that the ADC is enabled and is not busy converting. Single Con-
version mode must be selected and the ADC conversion complete interrupt
must be enabled.
2.
Enter ADC Noise Reduction mode (or Idle mode). The ADC will start a con-
version once the CPU has been halted.
3.
If no other interrupts occur before the ADC conversion completes, the ADC
interrupt will wake up the CPU and execute the ADC Conversion Complete
interrupt routine. If another interrupt wakes up the CPU before the ADC con-
version is complete, that interrupt will be executed, and an ADC Conversion
Complete interrupt request will be generated when the ADC conversion
completes. The CPU will remain in active mode until a new sleep command
is executed.
Note that the ADC will not be automatically turned off when entering other sleep modes
than Idle mode and ADC Noise Reduction mode. The user is advised to write zero to
ADEN before entering such sleep modes to avoid excessive power consumption. If the
ADC is enabled in such sleep modes and the user wants to perform differential conver-
sions, the user is advised to switch the ADC off and on after waking up from sleep to
prompt an extended conversion to get a valid result.
Analog Input Circuitry
The Analog Input Circuitry for single ended channels is illustrated in Figure 105. An ana-
log source applied to ADCn is subjected to the pin capacitance and input leakage of that
pin, regardless of whether that channel is selected as input for the ADC. When the chan-
nel is selected, the source must drive the S/H capacitor through the series resistance
(combined resistance in the input path).
The ADC is optimized for analog signals with an output impedance of approximately
10 k
Ω or less. If such a source is used, the sampling time will be negligible. If a source
with higher impedance is used, the sampling time will depend on how long time the
source needs to charge the S/H capacitor, with can vary widely. The user is recom-
mended to only use low impedant sources with slowly varying signals, since this
minimizes the required charge transfer to the S/H capacitor.
If differential gain channels are used, the input circuitry looks somewhat different,
although source impedances of a few hundred k
Ω or less is recommended.
Signal components higher than the Nyquist frequency (f
ADC/2) should not be present for
either kind of channels, to avoid distortion from unpredictable signal convolution. The
user is advised to remove high frequency components with a low-pass filter before
applying the signals as inputs to the ADC.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AT90USB1287-16AU 功能描述:8位微控制器 -MCU 128kB Flash 4kB EEPROM 48 I/O Pins 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
AT90USB1287-16AUR 功能描述:8位微控制器 -MCU 128K Flash 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
AT90USB1287-16ME 制造商:Atmel Corporation 功能描述:
AT90USB1287-16MU 功能描述:8位微控制器 -MCU 128kB Flash 4kB EEPROM 48 I/O Pins 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
AT90USB1287-64QFN 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:AT90USB1287 (AVR) 64 QFN device (2.7V VCC 5.5V)