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I2C versus SDI Diplays.

Posted: Sun May 12, 2019 8:23 pm
by gdt
Hello body,
in the past I've uded some I2C display (SH1106, SSD1306) with PIC18LF26K80 and no problem seen.
Now I'm trying to use the same I2C display but with PIC16F1455 or 16F1825 and in both cases, even the simple "ClearDisplay" flowchart is giving compiler error (FC7 v7.3.0.7):
ClearDisplay.png
(6.55 KiB) Downloaded 1793 times
.......
Distance Sensor 16F1455 V1.0.c: 220: (1250) could not find space (128 bytes) for variable _FCV_006e1_gLCD_SH1106_I2C1__DRAM0
Distance Sensor 16F1455 V1.0.c: 220: (1262) object "_FCV_006e1_gLCD_SH1106_I2C1__DRAM0" lies outside available data space (warning)
(908) exit status = 1
(908) exit status = 1
.......

After some troubleshooting I see that for I2C diplsys it needs to use PIC with more than 1K RAM. Is it correct or I'm missing something here?
If so, is there a way to reduce the amount of RAM used with I2C displays?

Thanks
Giuseppe

Re: I2C versus SDI Diplays.

Posted: Wed May 15, 2019 10:30 am
by gdt
Hello,
i would just somebody to confirm if I2C displays take so much amount of RAM or it's just a specific component issue.

Thanks
Giuseppe

Re: I2C versus SDI Diplays.

Posted: Wed May 15, 2019 8:20 pm
by kersing
I2C graphic display require ram to store screen contents. When displaying new information you are adding pixels to whatever is on screen. The controller needs to know what is already on screen to add the pixels. The amount of ram required depends on the number of pixels on the display.

Re: I2C versus SDI Diplays.

Posted: Wed May 15, 2019 9:09 pm
by gdt
Hello Kersing,
many thanks for sharing useful info.
I wanted just to make sure I wasn't missing any obvious settings.

Regards
Giuseppe