参数资料
型号: 20-101-1094
厂商: Rabbit Semiconductor
文件页数: 72/130页
文件大小: 0K
描述: MCU RCM4000 RABBITCORE
标准包装: 1
系列: RabbitCore®
模块/板类型: MPU 核心模块
适用于相关产品: RCM4000
产品目录页面: 619 (CN2011-ZH PDF)
其它名称: 316-1139
40
RabbitCore RCM4000
4.4 A/D Converter (RCM4000 only)
The RCM4000 has an onboard ADS7870 A/D converter whose scaling and filtering are
done via the motherboard on which the RCM4000 module is mounted. The A/D converter
multiplexes converted signals from eight single-ended or four differential inputs to Serial
Port B on the Rabbit 4000.
The eight analog input pins, LN0–LN7, each have an input impedance of 6–7 M
,
depending on whether they are used as single-ended or differential inputs. The input signal
can range from -2 V to +2 V (differential mode) or from 0 V to +2 V (single-ended mode).
Use a resistor divider such as the one shown in Figure 10 for the analog inputs.
Figure 10. Resistor Divider Network for Analog Inputs
The R1 resistors are typically 20 k
to 100 k, with a lower resistance leading to more
accuracy, but at the expense of a higher current draw. The R0 resistors would then be
180 k
to 900 k for a 10:1 attenuator. The capacitor filters noise pulses on the A/D
converter input.
The actual voltage range for a signal going to the A/D converter input is also affected by
the 1, 2, 4, 5. 8, 10, 16, and 20 V/V software-programmable gains available on each channel
of the ADS7870 A/D converter. Thus, you must scale the analog signal with an attenuator
circuit and a software-programmable gain so that the actual input presented to the A/D
converter is within the range limits of the ADS7870 A/D converter chip (-2 V to + 2 V or
0 V to + 2 V).
The A/D converter chip can only accept positive voltages. With the R1 resistors connected
to ground, your analog circuit is well-suited to perform positive A/D conversions. When
the R1 resistors are tied to ground for differential measurements, both differential inputs
must be referenced to analog ground, and both inputs must be positive with respect to
analog ground.
R0
LN0
AGND
LN1
ADC
BVREF
R0
C
R1
C
ADC
(RCM4000)
1
3
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20-101-1095 功能描述:模块化系统 - SOM BL2600 XD HOT SWAP 10/100 RoHS:否 制造商:Digi International 外观尺寸:ConnectCore 9P 处理器类型:ARM926EJ-S 频率:150 MHz 存储容量:8 MB, 16 MB 存储类型:NOR Flash, SDRAM 接口类型:I2C, SPI, UART 工作电源电压:3.3 V 最大工作温度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in
20-101-1104 功能描述:处理器配件 USB xd reader RoHS:否 制造商:Olimex Ltd. 产品:Cable 用于:
20-101-1105 功能描述:模块化系统 - SOM RCM4100 RabbitCore Module RoHS:否 制造商:Digi International 外观尺寸:ConnectCore 9P 处理器类型:ARM926EJ-S 频率:150 MHz 存储容量:8 MB, 16 MB 存储类型:NOR Flash, SDRAM 接口类型:I2C, SPI, UART 工作电源电压:3.3 V 最大工作温度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in
20-101-1110 功能描述:界面开发工具 Rio Protyping Board RoHS:否 制造商:Bourns 产品:Evaluation Boards 类型:RS-485 工具用于评估:ADM3485E 接口类型:RS-485 工作电源电压:3.3 V
20-101-1112 功能描述:模块化系统 - SOM RCM4010 Core Module RoHS:否 制造商:Digi International 外观尺寸:ConnectCore 9P 处理器类型:ARM926EJ-S 频率:150 MHz 存储容量:8 MB, 16 MB 存储类型:NOR Flash, SDRAM 接口类型:I2C, SPI, UART 工作电源电压:3.3 V 最大工作温度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in