How to detect presence of component in Embedded system?

[raghun]

Hi,
I am working on a safety critical system project for railways and I am using AT89C52 micro controller.

I use a number of buffers (74ls373), decoders (74ls138) , multiplexers(74ls157) etc. During self test of the I need to check the presence of each of the components mentioned above. If any of the component is removed from the system or it has failed to function then the AT89c52 need to detect the failed or removed component and the whole system need to go to fail safe mode.

Can anyone help me with this issue.
Raghu

 

[bobcat1]

Hi

Design your system using FPGA it will lower your cost and easy system test

All the best

Bobi

 

[skygazer]

hi raghun,
If you need to check the presence of any component on the board, you have to hook them up to your data bus.Then run some sort of loop back script which will apply proper bits to the inputs of the component, as well as read the output generated by the component.
You may have a table which maps inputs to outputs for all the components used in your design.The code can then check the outputs against the expected ones.

~~skygazer

 

[ragabs]

first tied output ports of micro to inputs of component
then tied input ports of micro to the cresponding output pins of component

apply test vector (as input to component) and check the cresponding output vector