message: Update README.md
  pressure sensor information
diff: ![plug in the nucleo](/ReadmePhotos/IMG_9312.jpg)
  * When programming over the Nucleo USB interface, the board emulates an ST-Link programming the MCU over SWD. Use these settings in the toolchain of your choice.
  -* The bringup code was written in the Arduino IDE environment with STM32duino installed and can be found here (disclaimer: this code is not part of the project and is pretty much unsupported, use at your own risk. The listing of hardware pin #defines at the top might be useful): [pcbreathe-bringup](https://github.com/inceptionev/pcbreathe-bringup/issues)
  +* The bringup code was written in the Arduino IDE environment with STM32duino installed and can be found here (disclaimer: this code is not part of the project and is pretty much unsupported, use at your own risk. The listing of hardware pin #defines at the top might be useful): [pcbreathe-bringup](https://github.com/inceptionev/pcbreathe-bringup)
  * The large power connectors on the PCB are JST VH type. [Purchase Link](https://www.amazon.com/gp/product/B07LBZ3LCR)
  * The smaller peripheral connectors on the PCB are JST XH type.
  * [Purchase link for 2/3/4/5-pin](https://www.amazon.com/gp/product/B06ZZ45G7G)
  * [Purchase link for 5/6/7-pin](https://www.amazon.com/gp/product/B079MJ1RYN)
  * Here is a crimper that can crimp both types of contacts. [Purchase Link](https://www.amazon.com/gp/product/B01N4L8QMW)
  * The buzzer requires an oscillating signal to make sound, it is designed for peak output at 2.4kHz. Take off the kapton cover at your own hearing risk.
  +* On the MPXV5004DP differential pressure sensors, the upper port is the positive measurement, and the lower port is the negative. The transfer function, assuming a 12-bit ADC, is P[kpa] = ADCcounts/819 - 1
  * The switched heater and solenoid outputs can support a resistive or inductive load up to 2A. Refer to schematic for pinouts.
  * The i2c sensor connectors are initially configured for providing 3.3V supply power to the sensors, but can be configured for 5V. Each sensor can have its own voltage; they do not need to be the same. If you need to switch to 5V, see the schematic for the resistors to change. Refer to schematic for pinouts.
  * The analog pressure sensors have an anti-aliasing filter value of 100Hz.
  