Hi all,
I am using Aduc848 Microcontroller for Data Logging application for logging data of 20 series connected 20V batteries. In this system I am facing problems of ADC accuracy, offsets,noise in readings and Controller Reset problem which occurs only when batteries are discharged. I have designed a circuit in which I used a common single +5v supply for pins AVDD & DVDD of Aduc848. These are analog & digital power supply pins of Aduc848 respectively.I made separate ground for analog section (AGND) and digital section(DGND). Both the grounds are shorted at only one point near +5v power supply.
So signal conditioning circuit,buffer,AGND pin of Aduc848 will have analog ground connected. I want to use an analog Multiplexer (MUX) to increase channels. Multiplexer has analog i/p channels having AGND & channel selection lines A0,A1,A2 which are connected to digital o/p ports of Aduc848 having DGND. MUX IC has V=,V- & GND pins.
So circuit is like this:
Voltage divider circuit using Resistors (Attenuator)-->Buffer and filter--->Multiplexer(MUX)--->Buffer and filter-->AIN1(Analog i/p channel of Aduc848.
So in this link I am sure that all except MUX will have AGND. I want suggestion about MUX GND.
MUX channels are selected by Aduc848 port pins P2.0,P2.1,P2.3 which are configured as Digital o/p ports.
SO MY QUESTIONS ARE:
1)Which ground should I connect to MUX GND? AGND or DGND?
2) Shall I use separate +5v supply for AVDD and DVDD pins of Aduc848?
3) How to prevent Resetting of Aduc848 when batteries are in Discharge mode?
Regards,
Prakod
I am using Aduc848 Microcontroller for Data Logging application for logging data of 20 series connected 20V batteries. In this system I am facing problems of ADC accuracy, offsets,noise in readings and Controller Reset problem which occurs only when batteries are discharged. I have designed a circuit in which I used a common single +5v supply for pins AVDD & DVDD of Aduc848. These are analog & digital power supply pins of Aduc848 respectively.I made separate ground for analog section (AGND) and digital section(DGND). Both the grounds are shorted at only one point near +5v power supply.
So signal conditioning circuit,buffer,AGND pin of Aduc848 will have analog ground connected. I want to use an analog Multiplexer (MUX) to increase channels. Multiplexer has analog i/p channels having AGND & channel selection lines A0,A1,A2 which are connected to digital o/p ports of Aduc848 having DGND. MUX IC has V=,V- & GND pins.
So circuit is like this:
Voltage divider circuit using Resistors (Attenuator)-->Buffer and filter--->Multiplexer(MUX)--->Buffer and filter-->AIN1(Analog i/p channel of Aduc848.
So in this link I am sure that all except MUX will have AGND. I want suggestion about MUX GND.
MUX channels are selected by Aduc848 port pins P2.0,P2.1,P2.3 which are configured as Digital o/p ports.
SO MY QUESTIONS ARE:
1)Which ground should I connect to MUX GND? AGND or DGND?
2) Shall I use separate +5v supply for AVDD and DVDD pins of Aduc848?
3) How to prevent Resetting of Aduc848 when batteries are in Discharge mode?
Regards,
Prakod