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[DM41] Screen tearing

Posted: Thu Feb 08, 2018 4:01 am
by reavy
There's a phenomenon on the DM41/L where, when in 12 MHz mode, the screen exhibits strange behavior when running something like the stopwatch. The best I can describe it is like tearing or flickering. This behavior isn't present when running in 48 MHz mode, and so I wonder if the 12 MHz mode is not fast enough to replicate the original calculator's speed or if there's some bug. (Presumably the 48 MHz mode causes the DM41 to run much faster than the HP-41.)

I notice this behavior on each of my two DM41 units and my DM41L. I noticed it on firmware v22 and after updating to v25 (these are the only two firmware versions I have run on the DMx series calculators).

Re: [DM41] Screen tearing

Posted: Tue Feb 13, 2018 12:23 am
by cappy
reavy wrote:
Thu Feb 08, 2018 4:01 am
There's a phenomenon on the DM41/L where, when in 12 MHz mode, the screen exhibits strange behavior when running something like the stopwatch. The best I can describe it is like tearing or flickering. This behavior isn't present when running in 48 MHz mode, and so I wonder if the 12 MHz mode is not fast enough to replicate the original calculator's speed or if there's some bug. (Presumably the 48 MHz mode causes the DM41 to run much faster than the HP-41.)

I notice this behavior on each of my two DM41 units and my DM41L. I noticed it on firmware v22 and after updating to v25 (these are the only two firmware versions I have run on the DMx series calculators).
Were you running a program at the time, or was the calculator just sitting there?
If running a program, you may want to post it here, so others can attempt to duplicate this.

Re: [DM41] Screen tearing

Posted: Tue Feb 13, 2018 6:03 am
by reavy
It’s only when running a program. The stopwatch function on the DM41 is the easiest way to reproduce it.

I will consider making a video of the phenomenon within the next few days and including a link here.

Re: [DM41] Screen tearing

Posted: Tue Feb 13, 2018 7:40 am
by Boub65
Hi
Is it the same as point 1) I describe here : viewtopic.php?f=10&t=311

Re: [DM41] Screen tearing

Posted: Wed Feb 14, 2018 7:35 am
by reavy
It does sound similar, but I believe I observed the effect on the DM15L, too.

Does the effect go away for you when setting the speed to 48 MHz?