WS0100 -TX (CPC WEG010016ELPP5N00100) Auto Reset

[mayur.k.vadukul]

I am using WEG010016ELPP5N00100 (WS0100 Controller IC) and graphic mode. The display is working correctly, however on odd occasion the display appears to get reset (Auto Reset assuming).

The display is defined as Two Line Display and the UART is enabled. It does get UART data whilst the system is working so the interrupt could occur whilst the data is being sent to the display. But I am processing the interrupt very quickly and it should not be Auto-Reset as after Auto Reset the display initializes with single line.

After completion of every message, I am re-initializing the display by hardware reset as I have ability on my hardware to perform Hard reset.

However, any ideas would be welcome.
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MVadukul

[Ttelmah]

You need to tell us a lot more about the PIC and the code you are using
to drive this.
Obvious things are that this is power related. Do you have the 0.1uF
capacitor immediately adjacent to the display that is recommended?.
Are you driving this in 4bit or 8bit mode?. If you are using 4bit mode, have
you looked at the recovery when there 'noise transfer mismatch' in the
data?. This is recommended at the head of each transfer proceedure to
ensure synchronisation.

[mayur.k.vadukul]

I am using 4 Bit interface and the PIC is PIC18F25K22.

The display is working absolutely fine but whilst the display is running, suddenly the display appears to be AutoReset. This gets corrected when in my code it is reinitializes. I have video of the display but not sure how can I post here.
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MVadukul

[temtronic]

Curious, I downloaded the LCD datasheet.
Interesting about the 'noise recovery' procedure. Never seen that before.
I'm wondering if the lower 4 bits could be tied to ground or VDD to prevent 'noise' ? Pretty sure I've seen this on other modules

[Ttelmah]

The reset is the difference between this display and the Hitachi compatible
devices. It is prone to hiccups sometimes when using the 4bit interface.
If you look at the Arduino and BBC drivers for these, the better ones
add sending the 5 nulls, and the notes say that this doesn't matter when
talking to the Hitachi compatible displays, but it is needed with these units.
There is no explanation anywhere of what causes this. I suspect it is
an internal lockup in the state machine inside the controller, however adding
this reset appears to be needed for these displays. If for example you are
using the flex_lcd driver, then at the start of each new screen just call
lcd_send_nibble(0); five times.
The fact that the manufacturer refers to noise when talking about this
is why I asked about whether the extra capacitor is present (unanswered).
They recommend like with the PIC itself that there is a 0.1uF ceramic
capacitor immediately adjacent to the supply connections.

[mayur.k.vadukul]

I am adding 5 times null on powering up the display but not every time. I was aware of capacitor 5 null commands but did not think it is required every time. I will try this and let you know.
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MVadukul