OLED through PCB Issue

tierfonorbital · October 23, 2022, 5:02pm

Doing an install with an oled in the Emitter section. Oled is wired through a 7 rail PCB (other 3 conductors are for blade). When I power up my chassis and put it in the hilt screen works fine. AS SOON as a connection to the PCB is severed )ie chassis is removed) the screen no longer works. Ive noticed also that if I do not put the chassis in the hilt JUST after boot, the screen does not work either. My ASSUMPTION is that if the board does not see a screen during boot up , it does not initiate display. And also when the board sees a screen disconnect it does the same. Wondering if there is an ‘always on’ line of code I can use or if any of you have thoughts.

profezzorn · October 23, 2022, 6:57pm

This isn’t really supported. ProffieOS used to completely freeze if it thought you had a display, but you didn’t. I made that better, but there is no support for connecting or disconnecting a display while ProffieOS is running.

That said, it may be something I can add support for. All that should be needed is to re-initialize the display if an error occurs… maybe…

tierfonorbital · October 23, 2022, 10:08pm

ANy tips on where to start digging around in the code to look for a re int in case of error? Just to start poking around…

profezzorn · October 23, 2022, 10:11pm

This is where the display init starts.

github.com

profezzorn/ProffieOS/blob/231bedb0453f9adcf0b4f9b9e9b927317d5eb4d0/display/ssd1306.h#L868


      
              bool connected = USBD_Configured();
              if (connected && !last_connected) controller_->usb_connected();
              last_connected = connected;
          #endif
          
          
  STATE_MACHINE_BEGIN();
              while (!i2cbus.inited()) YIELD();
              while (!I2CLock()) YIELD();
          
          
    // Init sequence
              Send(DISPLAYOFF);                    // 0xAE
              Send(SETDISPLAYCLOCKDIV);            // 0xD5
              Send(0x80);                          // the suggested ratio 0x80
          
          
    Send(SETMULTIPLEX);                  // 0xA8
              Send(HEIGHT - 1);
          
          
    Send(SETDISPLAYOFFSET);              // 0xD3
              Send(0x0);                                   // no offset
          
          
    Send(SETSTARTLINE | 0x0);            // 0x40 line #0

tierfonorbital · October 23, 2022, 10:12pm

Awesome thanks prof!

tierfonorbital · October 23, 2022, 11:27pm

Maybe something like this, that will display on after 4 seconds after loop is called

void loop() {
  oled.ssd1306WriteCmd(SSD1306_DISPLAYOFF);
  delay(4000);
  oled.ssd1306WriteCmd(SSD1306_DISPLAYON);
  delay(4000);

profezzorn · October 24, 2022, 12:17am

There are several things wrong with this.

There is no “oled” object, no ssd1306WriteCmd or SSD1306_DISPLAYOFF in proffieOS, but I can interpret that as pseudocode meaning “send displayoff command to oled”.
After the display have been off and unpowered, we need to set up all of it’s internal registers, not just turn it on again.
calling delay(4000) from loop() will freeze proffieOS for 4 seconds.

NoSloppy · October 24, 2022, 12:27am

Yeah, delay is generally a no-no I’ve learned.
FYI millis() holds the running time since the board has booted, and can be used in combination with a variable to check how much time has gone by