Re: LCD drivers



Paul Carpenter wrote:
> On Friday, in article <11jppu5dhvrg53e@xxxxxxxxxxxxxxxxxx>
> delman@xxxxxxxxxxxxxxx "Howard Delman" wrote:
>
>>I am considering using an MCU that has built in LCD drivers, but it only
>>implements 1:8 multiplexing. In other words, it has eight "common"
>>lines that are sequentially asserted. I need to connect it to an eight
>>character seven segment display. None of the displays that I have found
>>are designed for 1:8 multiplexing. Is it possible, and reasonable, to
>>use this MCU with a display that only has four commons (1:4
>>multiplexing)?
>
>
> To drive 8 characters with four commons suggests more segment drives required
> in other words the common drives TWO characters at the same time, so requires
> *14* segment drives (16 including DP).
>
> Does the micro support sufficient segment drives to match the LCD.
>
>
>> If so, would I use four consecutive commons, or every
>>other one? Would the appearance suffer in any way? And what if the
>>display is 1:3?
>
>
> The micro probably has the ability to drive UPTO 8 common drives and
> upto SOME number of segment drives, you must match this to your LCD
> and vice versa.
>
> The information should be in the micrprocessor and LCD datasheets and/or
> application notes.
>
> As you have not said WHICH micro and WHICH display you are using, no more
> detailed help can be given.
>
>
>>Thanks for any help.
>>Howard Delman
>
>

The MCU is not configurable for anything other than 1:8 or 1:9 drive.
It has more than enough segment drivers. I know I can leave the
unneeded segment drivers unconnected. It is the commons that concern me.

Howard
--
Delman Design
Digital design from conception to production
http://www.blueneptune.com/~delman
.

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