懷孕監(jiān)視器采用監(jiān)測荷爾蒙水平來實現(xiàn), 荷爾蒙水平監(jiān)測由三種標準方法:尿液, 唾液和體溫.每種檢測需要模擬前端來實現(xiàn).本文介紹了采用Cypress公司的CY8C38系列來開發(fā)懷孕監(jiān)視器的確具體方案,方框圖以及CY8C38 系列特性,框圖,CY8C38系列典型應用電路圖以及CY8CKIT-001 PSoC開發(fā)板主要特性,電路圖和材料清單.
Fertility Monitors are devices that monitor fertility levels by monitoring hormone levels. A fertility monitor may analyze hormone levels in bodily fluids, resistance in bodily fluids, basal temperature, or a combination of these methods. There are three standard methods for monitoring hormone levels:
Urine: Tests for luteinizing hormone surge
Saliva: Detects changing electrolyte levels
Temperature: Monitors basal body temperature to predict cycles
Each of these sensing methods require an analog front end (AFE) to perform the necessary measurements. Fertility Monitors are battery powered devices so active power consumption and sleep current are important considerations. A fertility monitor also includes a display, memory for storage of fertility reading history, serial communication such as USB. A touchscreen or capsense user interface may also be seen in fertility monitors.
PSoC? 3 and PSoC 5 provide a scalable platform which provides all the requisite circuitry to provide a configurable Fertility Monitor on Chip, including:
? High precision Analog front end, including a 0.1% accurate Voltage reference and up to 20 bits of resolution
? Circuitry for sequencing and driving LED for optical measurement of the test strip and the circuitry for reading the photodiode to create a full optical measurement system
? LCD direct drive and control
? Low active and sleep mode power consumption, with full operation down to 0.5V
? CapSense fully integrated
? FS USB
? On chip EEPROM
圖1. 懷孕監(jiān)視器框圖
PSoC?3 具有獨特的可配置模塊陣列，是真正的系統(tǒng)級解決方案，能夠通過單個芯片提供 MCU、存儲器、模擬和數(shù)字外設功能。
CY8C38 系列提供了一種新型的信號采集、信號處理和控制方法，并具有高精度、高帶寬和高靈活性等特點。其模擬功能涵蓋了從熱電偶信號(接近直流電壓)到超聲波信號的廣泛信號范圍。CY8C38 系列可以處理數(shù)十個數(shù)據(jù)采集通道以及每個 GPIO 引腳上的模擬輸入。CY8C38 系列還是一個高性能的可配置數(shù)字系統(tǒng)，具有 USB、多主控 I2C 以及 CAN 等接口。除了通信接口之外，CY8C38 系列還具有易于配置的邏輯陣列，至所有 I/O 引腳的靈活路由，以及高性能的單周期 8051 微處理器內核。通過分層式電路圖設計輸入工具 PSoC? Creator?，設計人員可以使用包含眾多預建組件和布爾基元的資料庫，輕松創(chuàng)建系統(tǒng)級設計。使用 CY8C38 系列不僅可以實現(xiàn)模擬和數(shù)字材料表的集成，而且只需通過簡單的固件更新，即可輕松納入最新的設計變更。
CY8C38 系列特性:
