I am trying to upload a welcome screen to my 240x64 LCD graphic module and am confused by the apparently contradictory advice in the different manual versions.

The module works fine and I can display a 240x64 image easily using image commands - so I have 240 x 64 / 8 bytes of good bitmap data which I would like to ;load as a welcome screen and I have tried inumerable combinations without success.

I send 'S' 'S' 'S'   <then some thing MSB first? LSB first?>  then 1920 bytes of known good bitmap and either nothing happens or "Data too long!" appears.

Please, what do I put between the 'S's'  and the 1920 bytes of data?

 It's LSB, MSB format, try this: "SSS\x80\x07", then following 1920 bytes of screen data, the "\x80\x07" are 2 bytes of hex value, LSB, MSB format, means 1920.

I tried that before (several times) but all I get is a blank screen and the original Digole welcome on next power up 

If I try ox07/0x80 I get Data Too Long!

I will try disabling the welcome screen, writing my 1920 bytes and then re-enabling to see if that works. I tried loads of combinations before postiong this but all without success. I am not using Arduino but a PIC32 and am programming in C on MPLABX. As I said. the display responds fine to all other commands graphics and fonts are good but I'm stuck with the welcome screen.

Thanks anyway for trying.

 The receiving buffer is only 256B on this module, you better add 100~300ms delay between very <256B data sent.

 OK thanks I'll try that when I get home. I'm away for a couple of days.

I'm surprised I'm overflowing the buffer as the same 1920 bytes loads under the 'DIM' command just fine and produces a perfect picture (and that's how I worked out the welcome screen I wanted) but I can soon write a loop to pause every 256 bytes.

Thanks again I will try it in a day or two.

 "SSS" command need additional time to write data to Flash, it's very slow compare with write to RAM.

For anyone with a monochrome 128x64 LCD with the Universal GLCD module, and using the C/Arduino library, I found that I had to go into DigoleSerial.h, and swap lines 495 and 496 of the downloadStartScreen function, to reverse the order of the LSB and MSB values sent to the adapter.

So, it went from:

...

write((uint8_t) (lon / 256));

write((uint8_t) (lon % 256));

...

to

...

write((uint8_t) (lon % 256));

write((uint8_t) (lon / 256));

...

Just in case this saves anyone else some frustration.

Jim

...

 Hello,

I've sent the data in small chunks with at least the delay you suggested but to no avail.

I've even tried one line at a time (240 bits - with a delay)  but no change from the original screen.

I suspect there is something missing from the command (after the SSS) and more than the byte count LSB first.

 Hello,

I'm still struggling with the welcome screen on my 240 x 64 monchrome. I have managed to display some garbage that has destroyed the origianl welcome message but not the sreen I want.

Any one got any ideas please?

'SSS' followed by 0x80, 0x07 and 1920 bytes of known good bitmap does not work no matter where or how long I spread delays through the trnsmission.

Does the bitmap data need to be in a diffeent format to th 'DIM' requirement? Does it need to be in command format nd not bitmap at all?

Thank you if you can think of anything. 

Try to use our online tools to get the welcome screen for 240x64 display module.

http://www.digole.com/tools/PicturetoC_Hex_converter.php

If that still not work for you, please post your code to us.

 Hello again,

I did use that tool to create my bitmap image and, as I said, it produces a perfect picture using DIM. I've tried all sorts of delays and something happens as random images appear, but I have never managed to get my welcome screen into flash.

I am working around it, at the moment, by disabling the welcome screen and loading my image using DIM as a first command.

The problem is that I use 1920 bytes of my MCU memory. It would be better in flash but I can't do it.

I don't want to attach 1920 bytes of pixel data but my code has been 'SSS' 0x80 / 0x07 / {1920 bytes of pixel bitmap}. I put delay loops after the 'SSS' then after the 0x80 / 0x70 as well as after each 30 bytes (one line on my 240 wide display), but to no avail.

I would prefer if you could get one of your own 240 x 64 displays and use SSS to load a welcome screen then post your successful result here please and I will work out from that how it's done as I've spent ages on trial and error. The manual and the forums seems to have abandoned the 240 x 64 and are devoted to the OLED colour screens. But the 240 x 64 is perfect in bright sunlight when it's even better than backlit and is a lovely display for the outdoor applications I have.

It's also not a question of closing the data block with 255, as my last two lines of screen data are all 0xFF anyway.

Many thanks again

Add 100ms delay after each exact 32 bytes of welcome screen image data sent (the total data is 1920 bytes, not include "SSS" and 0x80,0x07), the on board MCU only writing the image data to flash when a block (32/64 bytes) received or 1920 bytes reached, and during the writing process, all receiving data will be ignored, so, that's why you can't send data after each 32 bytes without a delay.

 That worked!!

Well done and many thanks. I broke it into exact 32 byte chunks and it loaded fine.

Thanks very much indeed I 've got my 1920 bytes back. These are very good displays for sunlight.