max6960 and LED matrix dot display module

[neko_whisker]

Hi,
I need your advice.

I have a max6960 and maxtrix dot led display module (common anode row, bi colour, 16x16 or 8x8).

I would like to know how to drive display module with max6960, but the problem is that max6960 is a cathode row display driver while the display module is designed to be driven by common anode row. I cannot find the display module (common cathode one) in Singapore.

So how do I go about it? Should I use inverter for both of max6960's row and column's output pins?

Thanks for your advice in advance.
neko_whisker

 

[tunedwolf]

From a quick look at the datasheet for the Max6960, I would say you will need a couple of transistors on the output of each driver pin, and drive the displays from them. I would think it easier to just ask Maxim for a sample of the driver for anode row displays, I'm sure they will be happy to send you a couple if you ask them nicely.

 

[neko_whisker]

Hi TunedWolf,

Thanks for your help.
Currently Maxim does not have a similar version for anode row.

May I know why the Inverter cannot be used? It is used as the opposite of states to drive.

regards

 

[tunedwolf]

If you use an inverter of any kind, including transistors to drive the pins, you will lose the ability to tweak the current to the displays using the features of the MAX6960. That will now have to be done externally with resistors. You may well also lose the ability, in the case of an inverter chip, to detect open/short led segments using the chip features. Using an inverter chip, is an unlikely solution due to the current requirements, but if you can find something that can handle the current that your leds are going to draw per output pin, and is within the total package dissipation, then go for it.

 

[hjames]

CA/CC for segment displays definitely matters when driving a single display, but for matrix displays?! If you swap the rows and columns, then isn't that all you need to do?

 

[tunedwolf]

Perhaps, depends on the actual display, if you were directly in control of what segments were to be lit at any one time it would be possible. Unfortunately in this case with this driver chip I don't think it's possible because of the type of display, i.e each row has a common anode or cathode, also as the chip is designed for a multi-stacked-tile of multicoloured leds so there will be far more column drivers versus row drivers. Then there are the physical aspects also, most of these types of stackable displays, that I have seen anyway, clip together with pin-outs set for the easiest routing, to swap them round would be very difficult, and will definately increase the cost of any board you may make for it.

 

[neko_whisker]

Hi TunedWolf,
Thank you for your great advice. I just had read all the way from top to down on the datasheet. You are right. Transistor must be used and like you say those reasons above, I begin to understand better. Thanks again.

Hope that you will be still around there in case of doubts.

Clement

 

[tunedwolf]

glad to have been of help