Mandar Limaye wrote:
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I just cant get it to work ,
I am using MAX7219 with 8051 :

1) Is there any specification about the type and length
of wires used for DIN , CS and CLK ?

There is a calculable maximum, depending on your cable type and drivers. The device will handle at least a metre of ribbon cable. In one system we have with the 7219, we have well over 10m of heavily buffered

2) I have noticed a peculiar behavior , when i try to
remove the plug from the mains socket , all the segments
start to glow .

That's what we engineers call a weird thing.... In reality, the chip is "dying" at that point, its behaviour is not well defined.


Which processor ? what access speed ? what algorithm ? how are you setting the chip up ? Have you observed the waveforms on the pins of your chip ??? Is the PSU OK (These devices ONLY work on +5V) ?

Steve