However one thing is baffling. The control word has an option to blank digit 1&3 or 2&4. Now what kind of an application would require this kind of a wonky blanking scheme ?

Hallo Raghunathan,

the SAA1064 can only drive the four displays in this multiplexing mode. A blinking over all four digits is not possible. I guess, it has to do with limitations of internal circuitry in terms of heat dissipation and current drive capability. So, the only way to provide a blinking is by this strange multiplexing scheme. It's not, that there is any relevant use of such strange blinking, but it's the only way to introduce a blinking at all, with this chip.

Of course, by changing internal circuitry a blinking over all four digits could be provided, somehow. But developers seem not to have had any motivation to do so...

Bye,
Kai