Do i run in timing-problems?

Projects General Guidance
1

Hi

Im planning to use 5x7 VFD Matixes, there are bi-color, so its basically a 5x14 Matrix, and just like a LED-Matrix

These are controlled by special VFD IC's which contains a 32bit Shift register.

If i want to use 6 Displays, i have to shift out 192 bits.

A Arduino running on 16MhZ, so one cycle is about 63ns!

Lets say i just want to multiplex 2 Lines, on all displays, would result in 384bits x 63ns = 0.025ms ! And thats only when the code has to do nothing else....

I fear that in the real projects this combination will result in "heavy flickering of the displays, because if i want to multiplex 2 lines individually per display, this would result in 0.15ms.

Is my theory right?

Would it be a better option, to use a single arduino per display (just the Atmega) and connect them per I2C?

2

If the VFD IC's have an internal multiplexed driver and shift register, you should not be repeatedly shifting out data. You only do that when you write something to the display. So there should be no flicker.

3

aarg:
If the VFD IC's have an internal multiplexed driver and shift register, you should not be repeatedly shifting out data. You only do that when you write something to the display. So there should be no flicker.

No, they don't have that, its just a 32bit Shift register with high-voltage sink outputs :confused:

4

sgt_johnny:
No, they don't have that, its just a 32bit Shift register with high-voltage sink outputs :confused:

Link to datasheet please...

5

This one here, i need this because my VFD is supplied with 35Volts.