Power Management
if(!SD_Read_Block(RP,ptrBP)){
SystolicPressure=(BPMem[0]<<8)+BPMem[1];
DyastolicPressure=(BPMem[2]<<8)+BPMem[3];
HeartBeat=(BPMem[4]<<8)+BPMem[5];
Hr=BPMem[6];
Min=BPMem[7];
Day=BPMem[8];
Month=BPMem[9];
MemoryDisplay(2);
} else{
Error(9);
}
}
***************************************************************************************
void GReadMemory (void){
ptrG=&GMem[0];
if(!SD_Read_Block(RG,ptrG)){
Glucose=(GMem[0]<<8)+GMem[1];
Hr=GMem[2];
Min=GMem[3];
Day=GMem[4];
Month=GMem[5];
MemoryDisplay(1);
} else{
Error(9);
}
}
10 Power Management
It is important to correctly implement the power source to control the analog and digital voltage for different stages in the system.
Even when the whole system is supplied with the same voltage, the motor and the control consume more electrical current. It
is necessary to separate the voltage source and implement the circuit’s isolation voltages and GNDs. Figure 22 shows the
principal circuit to supply voltage. The system receives 9 V and depending if the switch is ON or OFF, allows passing the
regulated voltage of 3.3 V with a capacitor coupling to ensure the voltage level and improve the signal integration.
Figure 22. Voltage and GND isolations
10.1 Power Management and the MC9S08LL16
The MC9S08LL16 microcontroller has an operating voltage of 1.8 V to 3.6 V that allows the LCD, SCI ,and SPI to work with
low power consumption. This device provides wait and stop modes.
The system provides three power sources from the principal voltage source.
• Integrated circuit voltage
• Motor and valve voltage
• Pressure sensor supply voltage
Implementing a Glucometer and Blood Pressure Monitor Medical Devices, Rev. 1, 4/2010
24
Freescale Semiconductor, Inc.
FREESCALE [ Freescale ]
