introduction Diabetes is a common chronic disease that seriously endangers human health. In recent years, the number of cases has increased year by year. Patients must regularly monitor blood glucose to control the disease and have targeted treatment. Blood glucose meters have become a common family medical device, and most of the blood glucose meters on the market are difficult to match in price and precision. With the development of electronic technology, a powerful and inexpensive blood glucose meter came into being. This article will introduce a new method for measuring blood glucose concentration using CTPIC function using Microchip PIC24 "GC" series MCU. Blood glucose meter test principle The method for detecting blood sugar level is a bioelectrochemical method. The principle is that after the blood glucose test strip is inserted into the blood glucose meter, a blood sample is dropped at the top of the test strip, and the glucose in the blood chemically reacts with the enzyme on the blood glucose test strip to generate electrons. Or micro current, The amount of electrons or the strength of the microcurrent increases as the blood glucose concentration in the blood increases. Test method for ordinary blood glucose meter By accurately measuring the magnitude of the weak current and calculating the corresponding concentration based on the relationship between the current value and the blood glucose concentration. In order to measure accurate current values, powerful analog signal conditioning circuits are often required. Figure 1: It can be seen from Figure 1 that the analog circuit of a conventional blood glucose meter requires: 1. At least two operational amplifiers with low offset, low temperature coefficient, and low bias current. 2. At least one 12-bit ADC or more, preferably 16-bit. Meeting these two conditions is a basic requirement of an ordinary blood glucose meter, but the cost of such a scheme is very high. PIC24CTMU blood glucose meter program description PIC24CTMU blood glucose test method The analog signal conditioning circuit does not need to be added, only the integrated CPUMU unit and high precision ADC of the MCU. As shown in Figure 2 below: The program is also based on the electrochemical principle of blood glucose measurement, but its implementation method has subverted the previous test method of blood glucose. This design introduces a single-chip design solution, with Microchip's latest PIC24F "GC" series MCU as the core, the peripheral circuit design is simple, and the test strip is directly connected to the MCUI/O port to complete a fast, high-precision, low-cost, Low-power blood sugar test. Figure 3 below is the hardware block diagram of the blood glucose meter: Specific principle: When a blood sample is dropped on the test strip, the glucose in the blood reacts with the enzyme on the test strip to generate a charge Q, and the charge has a linear relationship with the blood glucose concentration. Therefore, it is only necessary to measure the amount of charge on the strip. Know the concentration of blood sugar. A little different from most blood glucose testing methods here is the amount of charge measured, not the current value. The measured charge Q is used in the analog device and is provided entirely by the MCU. It mainly includes: high-precision analog-to-digital converter (ADC), programmable constant current source, digital processor and memory, high-precision timer, reference voltage source, etc. Figure 4 below is a diagram of the internal logic of the measured charge MCU: As you can see in Figure 3, the peripheral circuit is very simple, just a blood glucose test stand and a display. In this design, the master XIN chip selects Microchip's new PIC24FJ "GC" series MCUs, which have powerful advanced analog features and ultra-low power consumption. Advanced analog resources include 16-bit Σ-Δ ADC, 12-bit SAR ADC, 10-bit DAC, charge time unit (CTMU), two operational amplifiers, comparators, on-chip Vref, and so on. At the same time, it has ultra-low power consumption characteristics and multiple power management modes. The typical current is 40nA for deep sleep 3.3V, 32kHz for RTCC, and 400nA for 3.3V. In addition, the chip also integrates LCD driver, supports USBOTG, RTCC and other modules, Flash from 64kb-128kb, RAM8kb, adopts improved Harvard architecture, maximum operating speed up to 16MIPS (32MHz), integrated 17-bit x17-bit single-cycle hardware multiplier and many more. These resources fully meet the needs of a high-precision, low-power, low-cost blood glucose meter design. Dehydrated Scallion,Dehydrated Spring Onion Rings,Dehydrated Scallion Powder,Dried Green Scallion Xinghua Lvwei Foods Co.,Ltd , https://www.lvweifoods.com