HOWTO using SPI+I2C multi display (software mode).

[TrDA-hab]

0. About using SPI + I2C multi display (software mode).

• WIKI SPI.
• Step by step instructions for E-Paper Display.
• Tasmota commands for controlling displays.
• Tasmota examples for displaying information on the display.
• You can display the same information on all displays at once or display information individually on each display.

Clearing ESP32 / ESP8266 memory.

• It is recommended to use only ESP32 to work with the multi-display (software mode), the ESP8266 has very little RAM for such tasks.
• For the ESP32/ESP8266 to work correctly, you need to clear the memory. Clearing the memory must be done every time before flashing the Tasmota software.
• You need to download and install Python on your computer. After installing Python, follow these steps:
  • Installing the esptool utility:
    c:\users\admin>pip install esptool
  • Installing the latest updates:
    c:\users\admin\appdata\local\programs\python\python38-32\python.exe -m pip install --upgrade pip
  • Clearing memory in ESP32/ESP8266 (do not forget to specify your COM port):
    c:\users\admin\appdata\local\programs\python\python38-32\Scripts\esptool.py -p COM12 -b 115200 erase_flash

Other projects where multi display is used:

• Tasmota SPI multi display (hardware mode).
• Tasmota I2C multi display (hardware mode).
• ESP32 and 8 OLEDs arranged in a circle.
• Multiple displays on the I2C bus.
• 8 Multiplexed OLED /w ESP32 and U8g2.
• SPI OLED multiple displays with an Arduino.
• Multiple SPI based Displays with TFT_eSPI on an esp32.
• Multiple Displays with Arduino.
• Multiple OLED screens.
• Multiple OLED Displays / Multiplex TC9548.

Important information:

• In multi-display program mode, you can connect a maximum of three displays (different or the same).
• In slot 1, you can connect any Tasmota supported display (non-universal display). You must make all the necessary connections as usual.
• You can connect any universal driver to slot 2 and slot 3. You can see the list of universal display in this folder.

1. ESP32 + E-Papper (slot 1) + SSD1306 (slot 2).

How to use it.

Video of the display`s work:

https://youtu.be/DtdU9AR7CBk

ESP32 GPIO	Component	I2C display	SPI display
21	I2C SDA 1	SDA	-
22	I2C SCL 2	SCL	-
13	SSPI MOSI	-	DIN
18	SSPI SCLK	-	CKL
05	EPaper29 CS	-	CS

• Use PlatformIO and these defines in user_config_override.h:

#ifdef USE_RULES
#undef USE_RULES
#endif

#ifndef USE_SCRIPT
#define USE_SCRIPT
#endif

#define USE_I2C
#define USE_SPI
#define USE_DISPLAY
#define USE_DISPLAY_MODES1TO5
#define USE_DISPLAY_EPAPER_29
#define USE_UNIVERSAL_DISPLAY
#define USE_MULTI_DISPLAY

• Rename the platformio_override_sample.ini file to platformio_override.ini and save.
• In the platformio_override.ini file, comment out tasmota and uncomment tasmota32.
• And don't forget to include your com port number. Then compile and flash your ESP32.

• In the Tasmota firmware go to Consoles/Manage File system select and load the SD1306_display.ini file for the display in slot 2 (from the ... tasmota / displaydesc folder).

• In the Tasmota firmware go to Consoles/Edit Script, insert the display script, set Script enable and Save.

>D
>B
; load SD1306 driver on boot
dt [S2/SD1306_display.ini:]
; clear screen, switch to LCD font; set auto draw
dt [zf1s1D1]
; switch to display 1
dt [S1:]
>S
; switch to display 2
dt [S2:]
; show time
dt [x35y30tS]
; switch back to display 1
dt [S1:]
; show time
dt [x10y10tS]

2. Other variants that have been tested (09/30/2021).

!!! Attention: !!! the multi-display software mode is currently in testing mode.

• ESP32 + E-Papper (slot 1) + SSD1306 (slot 2) = works well.
• ESP32 + LCD1602 (slot 1) + SSD1306 (slot 2) = works well.
• ESP32 + LCD1602 (slot 1) + SH1106 (slot 2) + ILI9341 (slot 3) = works well (by gemu2015).
• ESP32 + SSD1306 (slot 1) + E-Papper (slot 2) = more tests needed.
• ESP32 + E-Papper (slot 1) + E-Papper (slot 2) = more tests needed.

!!! For your information only !!!

2.1 ESP32 + E-Papper (slot 1) + SSD1306 (slot 2) + BME280.

>D
hum=0
temp=0
press=0
>B
; load SD1306 driver on boot
dt [S2/SD1306_display.ini:]
; clear screen, switch to LCD font; set auto draw
dt [zf1s1D1]
; switch to display 1
dt [S1:]
>S
; switch to display 2
dt [S2:]
; show time
dt [x35y30tS]
; switch back to display 1
dt [S1:]
; show time
dt [x10y10tS]
; update display every TelePeriod
if upsecs%tper==0
then
dp2
dt [x10y40]%temp% C
dt [x10y60]%hum% %%
dt [x10y80]%press% mmHg
dt [d]
endif
>T
; get some telemetry values
hum=BME280#Humidity
temp=BME280#Temperature
press=BME280#Pressure 

2.2 ESP32 + LCD1602 (slot 1) + SSD1306 (slot 2).

>D
>B
; load SD1306 driver on boot
dt [S2/SD1306_display.ini:]
; clear screen, switch to LCD font; set auto draw
dt [zf1s1D1]
; switch to display 1
dt [S1:]
>S
; switch to display 2
dt [S2:]
; show time
dt [x35y30tS]
; switch back to display 1
dt [S1:]
; show time
dt [x0y0tS]

2.3 ESP32 + LCD1602 (slot 1) + SH1106 (slot 2) + ILI9341 (slot 3).

Best regards,
TrDA.