A reference design for blood pressure measurement, showcasing control, data acquisition, and connectivity features, not authorised for critical applications.
Blood pressure measurement is paramount in healthcare, serving as a fundamental pillar in the assessment of cardiovascular health. This essential practice goes beyond mere numerical values; it plays a pivotal role in the early detection of hypertension, often a silent and insidious threat. Monitoring blood pressure not only aids in risk assessment for cardiovascular diseases but also guides treatment strategies, facilitating timely interventions. Furthermore, it empowers individuals to take charge of their health by providing insights into the impact of lifestyle choices. In this context, the significance of blood pressure measurement extends far beyond numerical readings, encompassing the prevention, management, and optimisation of overall well-being.
The blood pressure monitor (BPM) reference design by Freescale Semiconductor illustrates the implementation of a system capable of measuring arterial blood pressure values. It showcases functionalities encompassing control, data retention, analogue acquisition, connectivity, and user interface interaction, all achieved through utilising various Freescale devices. It is important to note that this reference design solely serves as a proof of concept for this application. It is not authorised for use in safety-critical applications, including those under the U.S. Food and Drug Administration (FDA) class 3 categorisation. Manufacturers and designers incorporating Freescale (FSL) technology into their products must possess the requisite expertise to address safety, regulatory, and legal considerations associated with their applications and using Freescale devices in safety-critical contexts.
The reference design incorporates various elements that can serve as valuable references for future development, including USB communication utilising the MC9S08JM60 as a bridge, 2.4 GHz communication facilitated by the MC13202 ZigBee transceiver, MRAM communications, storage of user data in MRAM, implementation of an MRAM driver for memory access, user display integration through an OLED display, user interface interaction via the MPR083 proximity sensor, and audio feedback through two timer pulse-width modulator (TPM) modules. This solution offers the significant advantage of enabling developers to repurpose any hardware or software component for their unique applications, streamlining the design cycle and expediting development processes.
The design comprises essential components, including the BPM system itself, a cuff for blood pressure measurement, a PC software interface for data interaction, and the inclusion of a 1321x-SRB (sensor reference board) dedicated to ZigBee communication functionalities.
The design was strategically developed to segregate distinct system blocks, preventing the interference of coupling noise within the instrumentation amplifier lines. To facilitate debugging, power segmentation is achieved by employing 0 Ω resistors, which can be substituted with ferrite cores to effectively suppress EMI and attenuate noise originating from various sections of the board. Furthermore, a star configuration was implemented for ground distribution.
Freescale Semiconductor has tested this reference design. It comes with a Bill of Material (BOM), schematics, etc. You can find additional data about the reference design on the company’s website. To read more about this reference design, click here.