MSP430 Applicationin the medical equipment industry (6)
source: icbuy million core time: 2012-04-05-
ECG data acquisition circuit and
The ADS1258 element TI, using a low noise delta-sigma ADC architecture, orderly cycle of 16 channels, single cycle (zero delay) high-speed conversion rate programmable, rate of 1.8K~23.7KSPS per channel, no performance degradation. The built-in registers with monitoring system provides power supply voltage, temperature, voltage, gain, as well as the bias measurements, have been widely used for monitoring patients and ECG system, such as high precision, multi channel application, principle diagram of data acquisition module of the simplified as shown in figure 4. Pay attention to the analog signal input end of ADS1258 capacitor connected to a 2.2nF to bypass the ADC sampling current. The input signal of ¡À 1V, can not a divider resistance bridge, directly at its input end is connected with a protective resistor. External amplifier OPA365 single-ended output into a fully differential output to drive the ADC, but also to other 2.5V reference voltage is filtered and provides low noise reference voltage by using OPA350 buffer.
data storage and display
ADS1258 microcontroller reads the data collected through the P1 interface, a specific treatment data are stored in external memory. Data memory using the ATMEL's AT29LV1024, which has 1M of storage space and a power-off protection function, the data can be saved in the accident power-down or shut off the power supply situation. The system display ECG waveform and the analysis results of real-time acquisition through the liquid crystal display device. The system uses MAX3232 serial port expansion, and ultimately the ECG data to the hospital or the Centers for disease control, for hospitals to understand the condition of the patient.
The design of the system software
The main control module and the function module of ECG machine according to the system functional block diagram design, execution, the block diagram of system function of miniature twelve lead ECG machine as shown in figure 5.
