I am using an integrated 8 digit 7 segment display and using controller to drive the 7 segment. using only one 32 bit port.
7 bits- to drive the segments (a,b...g)
8 bits- to keep switching the common cathode pin for individual digit
and create the POV effect.
i am refreshing the each digit at the rate of 8milisecond.
1 millisecond for each digit.
but the issue is i can observe a mild ghost image in the digits which i keep blank in case not used.
(for eg:-when m displaying 2001 m not using the 4 digits before it and keeping it blank.)
I wanted to remove this ghost image problem.
Probable reason i can think of:-
transient Effect of the components used,since BJT is used to drive the LED's. So even after i have switched to different digit changing the common cathode (CC),still it keeps the LED on for few microseconds for ghost image to appear (decay voltage observed in CRO_decay voltage exists for around 300usec) (because i can see the ghost digit very prominently on the display)
I hope i was clear with my question
7 bits- to drive the segments (a,b...g)
8 bits- to keep switching the common cathode pin for individual digit
and create the POV effect.
i am refreshing the each digit at the rate of 8milisecond.
1 millisecond for each digit.
but the issue is i can observe a mild ghost image in the digits which i keep blank in case not used.
(for eg:-when m displaying 2001 m not using the 4 digits before it and keeping it blank.)
I wanted to remove this ghost image problem.
Probable reason i can think of:-
transient Effect of the components used,since BJT is used to drive the LED's. So even after i have switched to different digit changing the common cathode (CC),still it keeps the LED on for few microseconds for ghost image to appear (decay voltage observed in CRO_decay voltage exists for around 300usec) (because i can see the ghost digit very prominently on the display)
I hope i was clear with my question