ILI9341 with SW/HW SPI, 8/16 Bit parallel mode

Plons · Posted: Thu May 14, 2015 4:26 pm Post subject:

Lines 249 and 250 in the original ILI9341.inc

Plons · Posted: Thu May 14, 2015 5:20 pm Post subject:

In line 246 of the original ILI9341.inc you declare

Netzman · Joined: 25 Nov 2005 Posts: 112 Location: Graz

I've also found some errors and merged them with the ones you found (test program + library in the zip).
You're right, of course it should be !out instead of sts and &B instead of &H !
Also the DDR register address was wrong, should be Port - 1 instead of Port + 1.

Br

Plons · Posted: Thu May 14, 2015 6:23 pm Post subject:

Thanks Matthias !

One matter is still unclear to me: line 246, the

Plons · Posted: Fri May 15, 2015 12:37 am Post subject:

These displays have an on-board 3.3V regulator, so you can feed it with 5V on the Vcc pin.
The interface-signals are quite picky when it comes down to the max. voltage. Don't feed it directly from the IO-pins. I use a resistor of 470 Ohm with a 3V3 zener on each of the signals (no 4050 in stock). That 470 is too high for the 8MHz Sck in HW SPI. Will fix that tomorrow.
And because of the HW issues I didn't manage to test the latest version.

Tomorrow is another day.

Plons · Posted: Fri May 15, 2015 9:03 pm Post subject:

Found one other problem: With an SPI-clk at Xtal/2, the display doesn't work. At forst I suspected my PMI (Poor Mans Interface Wink

) to be the culprit. But it isn't. What happens is that the smart SPI peripheral in the AVR already signals that the job has been done, but, in reality, it's still moving out bits. So what I found with the oscilloscope was a level-change in the DC/RS line during the time that Sck was still at work. And that means TROUBLE !
@ the pictures: The scope triggers on DC/RS, blue trace, and the Clk is on the yellow trace.

Will be back with a solution ...

Nard

PS A .png with interface schematic was visible but ridiculous wide. It's now in the zip

Plons · Posted: Fri May 15, 2015 9:44 pm Post subject:

To fix that problem: replace the lines

Plons · Posted: Fri May 15, 2015 10:04 pm Post subject:

Hi Mathias,

I fear that your latest ILI9341_M328.inc still misses the !OUT vs STS.
This is what IMO the 3 macro's should look like:
(line 273 - 304)

albertsm · Joined: 09 Apr 2004 Posts: 5003 Location: Holland

when you use !IN and !OUT, bacom will transform to LDS/STS when required.

Plons · Posted: Fri May 15, 2015 11:42 pm Post subject:

You're spoiling us, Mark ! Very Happy

Until now, I always checked and double-checked if I did use the correct opcode for an IO-register in IO-space or extended IO-space. A luxury that I can skip those checks now.

It looks like this library is okay now. It was worth it.

Nard

Netzman · Joined: 25 Nov 2005 Posts: 112 Location: Graz

Plons · Posted: Sat May 16, 2015 3:49 pm Post subject:

Thanks for your explanation on the Const Lcd_spi_ctrl = Spcr matter. Is it correct to say that it has the same effect as the use of an alias like Lcd_spi_ctrl alias Spcr ?

Plons · Posted: Sat May 16, 2015 4:36 pm Post subject:

I took the zip from your original post and added two files: M328_ILI9341_SPI_revA.bas and ILI9341_M328_revA.inc. I didn't touch any of your originals. The zipped version is attached for download.

Cheers,

Nard

aphawk · Joined: 23 Jan 2010 Posts: 156 Location: Brazil

Nard and Mathias,

Thanks for your debugged version for Atmega328. This will be very usefull for many projects based on the Arduíno Uno hardware.

Paulo

Netzman · Joined: 25 Nov 2005 Posts: 112 Location: Graz

Hi Nard,

Thank you for your great effort debugging the library for the M328! I'll transfer the changes into the library for the next version release.