Meshtastic

Screen not Working

Hi I have mentioned this under access denied com3 but I can fix the access denied by chmod. The blank screen is still with me. I have two T-beam radios now and both show the same problem working on 0.6.4. Instead to seeing:

I2C device found at address 0x34
axp192 PMU found
I2C device found at address 0x3c
ssd1306 display found

on boot I only see the first two lines. No mention of ssd1306 or any display. Once I managed to see this but still I did not get to a live screen. So this could be a faulty screen, VCC and GND look correct but it could be something else. Or it could be that they need to be soldered in place and when I have done that I have accidentally connected across the pins.

If anyone else sees this same issue I would be interested in their solution. Thanks!

Hmm.

Can you post what you see on the serial console when your device boots? It should look approximately like this:

I2C device found at address 0x34
axp192 PMU found
I2C device found at address 0x3c
ssd1306 display found
done
Meshtastic swver=0.6.4, hwver=1.0-US
chip id detect 0x3
Detect CHIP :AXP192
OUTPUT Register 0x5f
AXP192 Begin PASS
DCDC1: ENABLE
DCDC2: ENABLE
LDO2: ENABLE
LDO3: ENABLE
DCDC3: ENABLE
Exten: ENABLE
----------------------------------------
DCDC1: ENABLE
DCDC2: ENABLE
LDO2: ENABLE
LDO3: ENABLE
DCDC3: ENABLE
Exten: ENABLE
SRC REG:0xcf
Charging enable is enable
Charging target-voltage : 0x2
 end when the charge current is lower than 10% of the set value
Charge current : 1000.00 mA
enable [0x40]val:0xdc
enable [0x41]val:0xff
enable [0x42]val:0x3b
Turning on screen
Read RTC time as 1 (cur millis 1538) valid=0

Hi I hit RST button this is it:
Emitting reboot packet for serial shell
▒▒Hbooted, wake cause 0 (boot count 1), reset_reason=reset
I2C device found at address 0x34
axp192 PMU found
done
Meshtastic swver=0.6.4, hwver=1.0-EU865
chip id detect 0x3
** Detect CHIP :AXP192**
** OUTPUT Register 0x5f**
** AXP192 Begin PASS**
DCDC1: ENABLE
DCDC2: ENABLE
LDO2: ENABLE
LDO3: ENABLE
DCDC3: ENABLE
Exten: ENABLE
----------------------------------------
DCDC1: ENABLE
DCDC2: ENABLE
LDO2: ENABLE
LDO3: ENABLE
DCDC3: ENABLE
Exten: ENABLE
SRC REG:0xcf
** Charging enable is enable**
** Charging target-voltage : 0x2**
** end when the charge current is lower than 10% of the set value**
** Charge current : 1000.00 mA**
** enab le [0x40]val:0xdc**
** enable [0x41]val:0xff**
** enable [0x42]val:0x3b**
** Read RTC time as 1 (c ur millis 1472) valid=0**
Connected to UBLOX GPS successfully
Both my radios show same sequence. I will update to 0.6.5 to see what happens. I was hoping to use these radios in Mammoth Lakes in the Fall! Thanks for all your help.

hmm - I’ve got bad news I guess. Something is wrong with either boards or the screens because at the beginning when we probe for devices we didn’t see the screen answer. The messages about the AXP192 mean that you’ve definitely got a correct TBEAM load installed.

Just to double check: if you put a voltmeter across Vcc and Gnd it says 3.3V? And the four pins are soldered at 3V3/GND/22/21 on the silkscreen? (and vcc is on the 3v3 position and gnd is on the gnd position - some screens are made with the opposite convention)

Thanks. I thought it was not a good sign. I have checked it against pictures and the pins look correctly aligned. I have put a voltmeter across Vcc and Gnd and I get 3.3V. I also tried Gnd and 22, 21 - both pins connected to gnd give 3.3V too. I do not know if this is important.
I have ordered the same radio/screen from Lilygo so in a few weeks I can check.

1 Like

hi feh123 if you measure Tbeam’s pin 21 or 22 against ground it’s normal that you get 3V3 as they are I2C pins which have pull-up resistors. Strange that your problem appears on both your boards. Hope you’ll sort it out! cheers!

I’m having this exact issue. I’ve tried it on four displays and its still not working. I’ve tried another board as well with the displays. Nothing. I have not sodered them…I was just seeing if I could test them out first using the pins they provided with the TBEAM…maybe that’s what I’m doing wrong?

My problem was solved when I soldered the pins in. All three OLED’s I bought then worked. I am using T-beams too.

2 Likes

Thanks. Yes. Unless you are very lucky holding them in will not work.