参数资料
型号: MC705JP7CPE
厂商: Freescale Semiconductor
文件页数: 159/164页
文件大小: 0K
描述: IC MCU 8BIT 224 BYTES RAM 28PDIP
标准包装: 13
系列: HC05
核心处理器: HC05
芯体尺寸: 8-位
速度: 2.1MHz
连通性: SIO
外围设备: POR,温度传感器,WDT
输入/输出数: 22
程序存储器容量: 6KB(6K x 8)
程序存储器类型: OTP
RAM 容量: 224 x 8
电压 - 电源 (Vcc/Vdd): 2.7 V ~ 5.5 V
数据转换器: A/D 4x12b
振荡器型: 内部
工作温度: -40°C ~ 85°C
封装/外壳: 28-DIP(0.600",15.24mm)
包装: 管件
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.
相关PDF资料
PDF描述
S912XEG128J2MAA MCU 16BIT 128K FLASH 16K 80QFP
MC9S12XD64MAA IC MCU 16BIT 64K FLASH 80-QFP
MC56F8322VFAER2 IC HYBRID CTRLR 16BIT 48-LQFP
MCF5207CVM166J IC MCU 32BIT RISC 144-MAPBGA
MC68908GZ16MFJE IC MCU 8BIT 16K FLASH 32-LQFP
相关代理商/技术参数
参数描述
MC705JP7CPE 制造商:Freescale Semiconductor 功能描述:IC 8BIT MCU 68HC05 2.1MHZ DIP-28
MC705K1CP 制造商:Motorola Inc 功能描述:16 PIN DIP INTEGRATED CIRCUIT
MC705L16CFUE 功能描述:8位微控制器 -MCU 8B MCU W/ EPROM RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
MC705P6ACDWE 功能描述:8位微控制器 -MCU MCU 176 BYTES RAM A/D RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
MC705P6ACDWE 制造商:Freescale Semiconductor 功能描述:8-Bit Microcontroller IC