programming serial lcd [2 Attachments]

Started by "aj-...@blueyonder.co.uk [piclist]" July 4, 2018
Has anyone had any experience using the erc802-1 series of serial (i2c) lcd modules ?

I have not yet succeeded with getting mine to display anything and any suggestions would be most welcome. This is what I am doing -

I am using the power-on reset with the reset input wired to +5v.

In software I wait for about 50ms after switch on, then execute code which produces the clock (yellow) and data (blue) signals shown on the attached scope screenshot. This sequence is Start, slave address with write (01111100), followed by 'getack'.

The getack routine switches the pic sda port to input (porta,4 open drain with 10k pullup), reads the sda bit (porta,4) and loops till it goes low.

You can see from the scope trace that the data does not go low. The state shown on the left of the screen (sck high, sda high) continues indefinitely, and the prog hangs up at this point.

I am beginning to wonder whether the module has been damaged. I have used the common parallel-data modules a lot, and when they are powered up without having been programmed they show a characteristic pattern on the screen - you can see the pixels, and some of the characters places on the first line appear blocked-out. But my serial module does not show this - it remains uniformly illuminated (grey) all over. Any ideas ?
Wow, I didn't know this list was still going!

I haven't used this series of LCD display, but I wonder if this link is
of any help?

http://esp8266-projects.org/2015/03/display-time-st7032i-i2c-lcd-display-html/
Colin

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On 04/07/2018 18:41:02, "a...@blueyonder.co.uk [piclist]"
wrote:

>[Attachment(s) <#TopText> from a...@blueyonder.co.uk [piclist]
>included below]
>
>Has anyone had any experience using the erc802-1 series of serial (i2c)
>lcd modules ?
>
>I have not yet succeeded with getting mine to display anything and any
>suggestions would be most welcome. This is what I am doing -
>
>I am using the power-on reset with the reset input wired to +5v.
>
>In software I wait for about 50ms after switch on, then execute code
>which produces the clock (yellow) and data (blue) signals shown on the
>attached scope screenshot. This sequence is Start, slave address with
>write (01111100), followed by 'getack'.
>
>The getack routine switches the pic sda port to input (porta,4 open
>drain with 10k pullup), reads the sda bit (porta,4) and loops till it
>goes low.
>
>You can see from the scope trace that the data does not go low. The
>state shown on the left of the screen (sck high, sda high) continues
>indefinitely, and the prog hangs up at this point.
>
>I am beginning to wonder whether the module has been damaged. I have
>used the common parallel-data modules a lot, and when they are powered
>up without having been programmed they show a characteristic pattern on
>the screen - you can see the pixels, and some of the characters places
>on the first line appear blocked-out. But my serial module does not
>show this - it remains uniformly illuminated (grey) all over. Any
>ideas ?