Logic Level shifter for 12864 display on Duet 2 Wifi

antlob

@bearer @Schmart First of all sorry for not replying until today, yesterday couldn't find time to continue. I know I say it everytime I write but I'm really grateful for all the help you've given me so far, without you gys I counldn't by any change connect the display.

I think that I've read in diagonal all the posts about this LCD and all the suggested help you adviced, even a guide to connect the Ender 3 to Duet Maestro. Since I was running RRF 3.1.1 and then installed @bearer RRF 3.0 I thought that maybe I needed to wipe and do a clean install. What I did was:

Erase the Duet
Using BOSSA uploaded the @bearer firmware version 2.05
Downloaded this menu https://github.com/mudcruzr/Duet-Maestro-12864-Menu-Files
Copy again all the sys and rest of menus

What happened?

The same issue but in a thread of another post @dc42 suggested to another person put in the terminal M918 P1 and then voilà the display worked. The funny thing is that in my config file at the end was the M918 P1 E-4 F2000000. What I did was take out the frequency parameter and the display worked.
On DWC the menu tab was not displayed.
The encoder works but cannot select anything, the press doesn't do anything.

Then I erased the Duet again and did a clean install of @bearer RRF 3.0. And have the following issues:

On reboot the display is blank (is lighted but with no text on the matrix).
I have to manually type M918 P1 E-4 and then the display works
The encoder works but can't select anything, nothing happens when I press the encoder button.
The display show correctly the temps, coordinates.
In DWC now I have the menu tab

My thoughts about my issues are the following:

The encoder press must have a command or something that I'm missing in the menus since they were made for a Duet Maestro. I know I have to dig in every menu file to adapt it to my Duet 2 Wifi.
I can't understand why in my config.g the M918 doesn't work

What I haven't find yet is if there's a guide to create menus and the usage of encoder. Could you give me a little assistance please?

A Former User

@antlob said in Logic Level shifter for 12864 display on Duet 2 Wifi:

Then I erased the Duet again and did a clean install of @bearer RRF 3.0. And have the following issues:

On reboot the display is blank (is lighted but with no text on the matrix).
I have to manually type M918 P1 E-4 and then the display works
The encoder works but can't select anything, nothing happens when I press the encoder button.
The display show correctly the temps, coordinates.
In DWC now I have the menu tab

would suggest one of us messed up the enc_sw connection and/or code. i didn't explicitly test the encoder as i won't use it, however its a simple normally open switch to ground, just like enc_a/b. starting to look like i won't revisit this for a couple of weeks (one handed bandit for a while)

antlob

@bearer said in Logic Level shifter for 12864 display on Duet 2 Wifi:

one handed bandit for a while

Sorry @bearer, since I'm from Spain and not a native English speaker don't understand the "one handad bandit for a while". Do you have, by any chance, the master of your fork so maybe I can dig a little bit and try to find out why the encoder's push button does not work?

A Former User

(temporarily disabled hand, so only one working hand left for a while)

anyways its all in the thread, i haven't forked the code
https://forum.duet3d.com/post/147841
https://forum.duet3d.com/post/147937

antlob

@bearer OK, hope you get better!

oliof

@antlob the encoder button is also something I had trouble with -- but other than with your issue, I got "ghost" clicks with the 12864 I tried. I blamed that on bad wiring at the time since I know that everything works fine on the Duet Maestro.

Considering the manual entry of M918 P1 -- I had a similar issue with the 12864 on Maestro where the first command would enable the screen but the graphics would be corrupted. I solved this by doing

M918 P1
G4 P1000
M918 P1

I.e., initializing twice with a one second pause in between.

(coincidentally, I tried my Creality Minipanel this afternoon and while I didn't get the display to show anything, I got Encoder wheel and button working -- tested with a very simple main menu that just calls Macros running various M291 commands, i.e. creating disimissable popups I can observe in DWC).

A Former User

for what its worth i had no issues on the Maestro, beyond the polarity on the geeetech display headers being wrong and the encoder skipping two entries which was solved by E2 in M918 as such I didn't bother testing on the Wifi board.

I'm guessing dc42 wil be done with his 756x stuff by the time I get the cast* off and will poke it some more then

*) give the kids alcohol before the sports get them!

antlob

@oliof Thanks! Yesterday came to the same conclusion as you did the same, initializing twice and it works. About the button I dig in some Arduino forums and tested the encoder, when I press it closes a circuit to ground so the hardware is fine. In my case, the rotary works just fine is only the switch button.
When I donwloaded @bearer's patch, in it is clearly defined that the pin used for the encoder switch is number 8 and that it connects to CONN_LCD 10.

+// 12864 LCD
+// The ST7920 datasheet specifies minimum clock cycle time 400ns @ Vdd=4.5V, min. clock width 200ns high and 20ns low.
+// This assumes that the Vih specification is met, which is 0.7 * Vcc = 3.5V @ Vcc=5V
+// The Duet Maestro level shifts all 3 LCD signals to 5V, so we meet the Vih specification and can reliably run at 2MHz.
+// For other electronics, there are reports that operation with 3.3V LCD signals may work if you reduce the clock frequency.
+// ST7920 doesn't allow SCK/MISO signals when CS is not asserted, therefore the AND gate on the Maestro
+constexpr uint32_t LcdSpiClockFrequency = 2000000; // 2.0MHz -- Top View --
+constexpr Pin LcdCSPin = 7; //connsd.7 --> gate -> exp1.4
+constexpr Pin LcdBeepPin = 60; //connlcd.4 -> exp1.1
+constexpr Pin EncoderPinA = 85; //connlcd.8 -> exp2.5
+constexpr Pin EncoderPinB = 25; //connlcd.6 -> exp2.3
+constexpr Pin EncoderPinSw = 8; //connlcd.10 -> exp1.2

Seeing other diagrams in this post and also Schenk's tried out to connect the ENC_SW to the original CONN_SD.7 and it worked! But now I had an important issue, the 3.3v that should go to the LCD_CS were in an open circuit, but, nevertheless the LCD worked, maybe my model was one of the ones that can operate with 3.3 v signals. Now, since LCD_CS was always on 3.3 v, and it needed to be for the AND gates to work, I connected it directly to a 3.3 v of the expansion and now the display starts just fine and have even taken the delay in the config.g. I assume that on power up, the M918 preceeds the initialization sequence in the Duet and therefore we had to make a delay in order of it to work. I bet that if you take the first M918 and just use a delay of 2 seconds it will work just fine.

So, my wiring is as of @bearer's patch and schematics but connecting EXP1.1 to CONN_SD.7 and the SN74HCT08DR 2A or pin4 to a 3.3 v source.

Now I have to test the SD card, need to find another one and see if I can read it.

antlob

@bearer I solved, not in a fancy way but it works. Many thanks!

A Former User

Not sure I quite followed you there, but sounds like the rrf3 binary may have been built before i swapped the two pins

antlob

@bearer I think so and it makes sense since the patch says v2.05. The funny thing is that when I uploaded v2.05 the encoder switch didn't work also, maybe was bad wiring from my part, since I'm on a breadboard.

Just tested the SD card and works perfect, remembered I had another in an old phone.

I will solder now and make the wires. Again, many thanks guys. @bearer or @oliof if in the future you want my schematic (the change I made from @bearer's) I'll post it.

oliof

Please post what you have (-;

antlob

@oliof Sorry for taking so long to reply. Couldn't make some time until today to return to this personal project. The change I made from @bearer schematic is ENC_SW and LCD_CS pins, below the image with the changes. I think this could only work for @bearer's RRF3 https://www.dropbox.com/s/f7fjuu7f0wcf7dc/Duet2CombinedFirmware-rrf3-lcd.bin?dl=1.

The only issue I find is that when accesing the SD card on the LCD12864 some lines appear on the display and have to clean them by manually entering M918 P1, even make a macro to just run it.
I'll be looking regurlarly at this posts in case anyone needs help or when @dc42 uploads his 3.2 version. See you guys around and again many thanks to everyone!

oliof

If you get artifacts when accessing the SD card slot, it's likely noise on the SPI connection. Try shielded it at least twisted cables.

antlob

@oliof OK, thanks for the tip! Surely is that now that you mention it. I did the circuit soldering wire graps and the rest is ribbon cable unshielded.

seraser

Tested 12864 fysetc mini in beta 3.2.2 duetwifi and dont work @dc42 connected as you sugested in previous post, M122 dont report error.

Try P1 and P2 with M918 and dont work.

Schmart

@seraser said in Logic Level shifter for 12864 display on Duet 2 Wifi:

Tested 12864 fysetc mini in beta 3.2.2 duetwifi and dont work @dc42 connected as you sugested in previous post, M122 dont report error.

Try P1 and P2 with M918 and dont work.

Please post your exact config line for the M918 command.

I'm not sure of the Duet Wifi situation and what display support it currently includes. Did you build the firmware yourself?
P2 is definitely the display type you want.
If you are sure of the electrical connections, logical levels and voltage levels, then trying R6 for the resistor ratio and playing around with the C parameter (contrast 0-100) could work.
Perhaps starting with a slow SPI frequency (F parameter) also helps.

So something like M918 P2 R6 C60 F200000 may just work.

seraser

@Schmart thank you for your response.

Changelog of 3.2 beta 2 says:

Supports ST7567-based 12864 displays on Duet Maestro and Duet WiFi (thanks to SchmartMaker for writing the ST7567 driver code)

So Im testing with 2.1 and 1.2 versión of fysetc mini 12864 with the pin asignement by @dc42, exp1 of mini to LCD exp in duet and exp2 mini to sd exp of duet, direct conection.

But something is not good, not work with your M918 line and if I rotate the encoder duet restart, maybe shorcut, with two LCDs.

oliof

If the encoder turning causes a reset, the wires might be turned 180 degrees.

seraser

@oliof I used dc42 pin asignement.