參數(shù)資料
型號： MC68HC705JJ7CP
廠商： FREESCALE SEMICONDUCTOR INC
元件分類： 微控制器/微處理器
英文描述： 8-BIT, OTPROM, 2.1 MHz, MICROCONTROLLER, PDIP20
封裝： PLASTIC, DIP-20
文件頁數(shù)： 159/164頁
文件大?。?/td> 1165K
代理商： MC68HC705JJ7CP
Analog Subsystem
MC68HC705JJ7 MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
94
Freescale Semiconductor
8.11 Port B Interaction with Analog Inputs
The analog subsystem is connected directly to the port B I/O pins without any intervening gates. It is,
therefore, possible to measure the voltages on port B pins set as inputs or to have the analog voltage
measurements corrupted by port B pins set as outputs.
8.12 Port B Pins as Inputs
All the port B pins will power up as inputs or return to inputs after a reset of the device since the bits in the
port B data direction register will be reset.
If any port B pins are to be used for analog voltage measurements, they should be left as inputs. In this
case, not only can the voltage on the pin be measured, but the logic state of the port B pins can be read
from location $0002.
8.13 Port B Pulldowns
All the port B pins have internal software programmable pulldown devices available dependent on the
state of the SWPDI bit in the mask option register (MOR).
If the pulldowns are enabled, they will create an approximate 100
A load to any analog source connected
to the pin. In some cases, the analog source may be able to supply this current without causing any error
due to the analog source output impedance. Since this may not always be true, it is therefore best to
disable port B pulldowns on those pins used for analog input sources.
8.14 Noise Sensitivity
In addition to the normal effects of electrical noise on the analog input signal there can also be other
noise-related effects caused by the digital-to-analog interface. Since there is only one VSS return for both
the digital and the analog subsystems on the device, currents in the digital section may affect the analog
ground reference within the device. This can add voltage offsets to measured inputs or cause
channel-to-channel crosstalk.
To reduce the impact of these effects, there should be no switching of heavy I/O currents to or from the
device while there is a critical analog conversion or voltage comparison in process. Limiting switched I/O
currents to 2–4 mA during these times is recommended.
A noise reduction benefit can be gained with 0.1-
F bypass capacitors from each analog input (PB4:1) to
the VSS pin. Also, try to keep all the digital power supply or load currents from passing through any
conductors which are the return paths for an analog signal.
相關(guān)PDF資料
PDF描述
MC68HC705JJ7S 8-BIT, UVPROM, 2.1 MHz, MICROCONTROLLER, CDIP20
MC68HC705K1DWR2 8-BIT, OTPROM, MICROCONTROLLER, PDSO16
MC68HC705K1CP 8-BIT, OTPROM, MICROCONTROLLER, PDIP16
MC68HC705K1P 8-BIT, OTPROM, 2 MHz, MICROCONTROLLER, PDIP16
MC68HC705K1DW 8-BIT, OTPROM, MICROCONTROLLER, PDSO16
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC705JP7CDW 功能描述:IC MCU 8BIT 28-SOIC RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:HC05 其它有關(guān)文件:STM32F101T8 View All Specifications 特色產(chǎn)品:STM32 32-bit Cortex MCUs 標(biāo)準(zhǔn)包裝:490 系列:STM32 F1 核心處理器:ARM? Cortex?-M3 芯體尺寸:32-位 速度:36MHz 連通性:I²C，IrDA，LIN，SPI，UART/USART 外圍設(shè)備:DMA，PDR，POR，PVD，PWM，溫度傳感器，WDT 輸入/輸出數(shù):26 程序存儲器容量:64KB（64K x 8） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:10K x 8 電壓 - 電源 (Vcc/Vdd):2 V ~ 3.6 V 數(shù)據(jù)轉(zhuǎn)換器:A/D 10x12b 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:36-VFQFN，36-VFQFPN 包裝:托盤 配用:497-10030-ND - STARTER KIT FOR STM32497-8853-ND - BOARD DEMO STM32 UNIV USB-UUSCIKSDKSTM32-PL-ND - KIT IAR KICKSTART STM32 CORTEXM3497-8512-ND - KIT STARTER FOR STM32F10XE MCU497-8505-ND - KIT STARTER FOR STM32F10XE MCU497-8304-ND - KIT STM32 MOTOR DRIVER BLDC497-6438-ND - BOARD EVALUTION FOR STM32 512K497-6289-ND - KIT PERFORMANCE STICK FOR STM32MCBSTM32UME-ND - BOARD EVAL MCBSTM32 + ULINK-MEMCBSTM32U-ND - BOARD EVAL MCBSTM32 + ULINK2更多... 其它名稱:497-9032STM32F101T8U6-ND
MC68HC705JP7CP 制造商:Rochester Electronics LLC 功能描述: 制造商:Freescale Semiconductor 功能描述:
MC68HC705K1CDW 制造商:Motorola Inc 功能描述:
MC68HC705KJ1CDW 功能描述:8位微控制器 -MCU 8 Bit 4MHz 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(shí)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
MC68HC705KJ1CP 功能描述:IC MCU 4MHZ 1.2K OTP 16-DIP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:HC05 其它有關(guān)文件:STM32F101T8 View All Specifications 特色產(chǎn)品:STM32 32-bit Cortex MCUs 標(biāo)準(zhǔn)包裝:490 系列:STM32 F1 核心處理器:ARM? Cortex?-M3 芯體尺寸:32-位 速度:36MHz 連通性:I²C，IrDA，LIN，SPI，UART/USART 外圍設(shè)備:DMA，PDR，POR，PVD，PWM，溫度傳感器，WDT 輸入/輸出數(shù):26 程序存儲器容量:64KB（64K x 8） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:10K x 8 電壓 - 電源 (Vcc/Vdd):2 V ~ 3.6 V 數(shù)據(jù)轉(zhuǎn)換器:A/D 10x12b 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:36-VFQFN，36-VFQFPN 包裝:托盤 配用:497-10030-ND - STARTER KIT FOR STM32497-8853-ND - BOARD DEMO STM32 UNIV USB-UUSCIKSDKSTM32-PL-ND - KIT IAR KICKSTART STM32 CORTEXM3497-8512-ND - KIT STARTER FOR STM32F10XE MCU497-8505-ND - KIT STARTER FOR STM32F10XE MCU497-8304-ND - KIT STM32 MOTOR DRIVER BLDC497-6438-ND - BOARD EVALUTION FOR STM32 512K497-6289-ND - KIT PERFORMANCE STICK FOR STM32MCBSTM32UME-ND - BOARD EVAL MCBSTM32 + ULINK-MEMCBSTM32U-ND - BOARD EVAL MCBSTM32 + ULINK2更多... 其它名稱:497-9032STM32F101T8U6-ND
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