Re: LCD display Busy Flag


cbarn24050@xxxxxxx wrote:
Sagaert Johan wrote:

Hi

Can i check the busy flag of the display while continously keeping the
Enable high or should i pulse the enable ?

Johan

You need to strobe the enable. Someone else has mentioned that you dont
need to use it if you use a timer, this is fine for small displays (up
to 16 chars for a 2mS timer) or if you can accept a short delay in
updating. If you need a fast update on a larger display, say if you
were editing text or monitoring real time data, you need to reduce the
timer to 50uS and use the busy flag with a character buffer.

Strobing the enable isn't such a big deal anyway, if you intend to busy
wait. No need to optimize a delay loop :)

I agree that a timer based solution is best suited to smaller displays,
although with a suitably fast processor, bigger sized displays can be
handled fine. Right now, I'm working with a 4x20 character display.
Using a 2kHz timer interrupt, I get 25 screen updates/second, which is
plenty for the slow LCD. Interrupt overhead is about 2
usecs/character,resulting in 0.4% CPU utilization.

.

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