PMOD DPG1Reference Manual

Digilent PMOD DPG1（修订A）是差异压力表。与NXP的MP3V5010DPpiezoresistive transducer and Texas Instrument'sADCS747612位模数转换器，您可以检测到两个端口之间的压力发生变化并将数字信息发送给您的系统板。

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• Differential piezoresistive transducer
• 12-bit ADC
• 0至10 kPa差压范围
• 温度补偿和校准
• 带有SPI接口的6针PMOD连接器
• 遵循Digilent PMOD接口规范类型2

PMOD DPG1旨在检测从0 kPa到10 kPa的差压力。它使用嵌入式的12位ADC为用户提供了传感器上两个端口之间测量压力差的数据流。

Note¹- Data in the Typical Column uses V_CCat 3.3V unless otherwise noted
Note²- Where the pressure at P1 (top nozzle) is greater than the pressure at P2 (bottom nozzle)
Note³- Output voltage corresponding to a pressure differential of 0 kPa
Note⁴- CPOL = 0, CHPA = 0
Note⁵- Normal operation with V_CCat 3.3V

The Pmod DPG1 communicates with the host board via theSPI protocolwith SPI Mode 0 (CPOL = 0, CPHA = 0). The 12 bits of digital data are sent to the system board in 16 clock cycles with the most significant bit first. For the embedded ADC7476, each bit is shifted out on each falling edge of the serial clock line after the chip select line is brought low with the first four bits as leading zeroes and the remaining bits representing the 12 bits of data. Thedatasheet for the ADC7476建议对于更快的微控制器或DSP，串行时钟线首先被带到高状态，然后在芯片选择线倒塌后被降低，以确保第一位有效。

As a differential pressure module, it should be noted that the Pmod can only accept a certain range of pressure differences without damaging the internal piezoresistive silicon. When the Pmod is laid on a flat surface such that transducer is above the PCB, the top most nozzle is P1 (the receiving nozzle to detect fluctuating pressure) and the bottom most nozzle is P2 (the pressure reference nozzle for P1). The pressure at P1 is recommended to be between 0 and 10 kPa above the pressure present at P2. Pressures outside of this range may cause permanent damage to the device.

To convert the serial data stream back into a corresponding pressure, users may use the following equation:

PMOD DPG1上嵌入式MP3V5010的建议压力差范围在0 kPa和10 kPa之间，因此它非常适合诸如测量Venturi仪表内部的小压力变化，作为一种用于检测到何时接触的应用，以示意测量的应用。或确定正常人肺施加的气压（假设您不是小号手，也不是在需要高于平均肺部压力的另一个领域）。值得注意的是，PMOD DPG1无法测量汽车或自行车轮胎内部的气压。

可以从国家生物技术信息中心找到人类肺部压力的参考文章，对于有兴趣的人的参考文章。这里。

Additionally, the Pmod DPG1 is only able to measure dry fluids, such as air, as opposed to being able to measure water pressure.

But what is the lowest pressure that the Pmod DPG1 can detect? With an embedded 12-bit ADC that is powered at 3 V, the LSB will have a corresponding voltage of 0.732 mV, but the MP3V5010 has a listed sensitivity of 270 mV per kPa, or equivalently, 0.270 mV per Pascal. This means an LSB change will not occur until an approximate change of 3 Pascals of pressure occurs. Based on Wikipedia's list oforders of magnitude of pressure, a U.S. dollar bill exerts approximately 1 Pascal. Additionally, the lung air pressure difference of a normal breath from a person is approximately 300 Pascals, so the module is very capable of measuring very small changes in pressure.

PMOD DPG1能够将12位数据的每秒1 msa转换为1 msa，但是对1 kPa的步骤更改的换能器响应时间为1 ms。压力的较小变化将使换能器更换其输出电压所需的时间更少。

Any external power applied to the Pmod DPG1 must be within 2.7 V and 3.3 V to ensure that the on-board chips operate correctly; however, it is recommended that Pmod is operated at 3.3 V since an embedded regulator reduces the 3.3 V down to 3 V for the various embedded components

The pins on the pin header are spaced 100 mil apart. The PCB is 1.0 inches long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header. The transducer nozzles extend an additional 0.25 inches and the height of the transducer extends 0.375 inches above the PCB.

The schematics of the Pmod DPG1 are available这里。有关ADC的其他信息，包括通信模式和芯片的特定时间，可以通过查看其数据表来找到这里。Similarly, the datasheet for the transducer can be found这里。

Example code demonstrating how to get information from the Pmod DPG1 can be found这里。

如果您对PMOD DPG1有任何疑问或评论，请随时将其发布在适当的部分（“附加董事会”）下Digilent Forum。