Introduce ..

This is an advanced feature that allows users to interfere into the output controller by pin mapping on ESP32 to ESPrtk ..

In this way, the selection and placement of the output pins on ESP32 will not depend on the default configuration, making it easier for users to redesign their own ESPrtk PCB board.

This is a system configure and it is hidden when accessed in the Web Configure.
To be able to access this page, after the login Profile, type http://192.168.4.1/system  to enter System page.

This page showing with a black background interface , users can drag and drop ESP32 pins into the frame corresponding to ESPrtk. Click “Save” button to save the configuration.

Or user can enter the JSON string into the text field and click “Save as JSON” to save the configuration.

After that, ESPrtk will check the logic, if there is no error, it will print “Config GPIO save success” in the Submit status box.

At the same time, it export a JSON string, clicks “Copy output” to save it in Clipboard as text and paste it anywhere.

Configure data will store in FLash in ESP32 .

Video

Default config from ESPrtk Factory (JSON):

This is the default configuration on ESPrtk, you may need it to restore to the default configuration state, just Copy it, paste it into the JSON box and click “Save as JSON”.

(Copy all text in box)

{ "CWB_Button" : "13" , "RX_UART0" : "3" , "MOSI_SD_Card" : "19" , "MOSI_LoRa_Ethe" : "33" , "TX_UART0" : "1" , "MISO_SD_Card" : "39" , "MISO_LoRa_Ethe" : "35" , "RX_UART1" : "17" , "SCK_SD_Card" : "18" , "SCK_LoRa_Ethe" : "25" , "TX_UART1" : "5" , "CONNECT_LED" : "15" , "CS_SD_Card" : "23" , "RX_UART2" : "16" , "ERROR_LED" : "12" , "CS_LoRa" : "32" , "TX_UART2" : "4" , "TX_UART3" : "14" , "CS_Ethernet__PWR_GSM" : "0" , "SCL_I2C" : "22" , "SCL_OLED" : "27" , "RST_LoRa_Ethe" : "2" , "SDA_I2C" : "21" , "SDA_OLED" : "26" , "DI0_LoRa" : "34" , "RX_UART3" : "36" }

The above configuration will correspond to the diagram below:

Please read ESPrtk datasheet for detail information about pinout on ESPrtk.

• ESPrtk datasheet and documents
• Connect ESPrtk to RTK receiver and some other modules

Application .

Besides helping make PCB design more flexible, this feature allows ESPrtk to be compatible on all hardware boards with different pinout designs.

For example #1: WEMOS / Lolin ESP32 OLED board.

This module is integrated OLED LCD on GPIO5 (SDA_2) and GPIO4 (SCL_2) on board ( ESPrtk also supports OLED display ).

However, by default pin GPIO5 and GPIO4 on ESP32 are TX_UART1 and TX_UART2 of ESPrtk (see default JSON above) so we will swap the configuration on 6 pin, specifically:

• SCL_OLED : from  27   to 4
• SDA_OLED : from  26  to 5
• TX_UART2 : from  4 to 25
• TX_UART1 : from  5 to 26
• RX_UART1 : from  17 to 36
• RX_UART3 : from  36  to 17

And other pins remain the same as default.

The JSON code should be : 

(copy all text in box)

{ "CWB_Button" : "13" , "RX_UART0" : "3" , "MOSI_SD_Card" : "19" , "MOSI_LoRa_Ethe" : "33" , "TX_UART0" : "1" , "MISO_SD_Card" : "39" , "MISO_LoRa_Ethe" : "35" , "RX_UART1" : "36" , "SCK_SD_Card" : "18" , "SCK_LoRa_Ethe" : "27" , "TX_UART1" : "26" , "CONNECT_LED" : "15" , "CS_SD_Card" : "23" , "RX_UART2" : "16" , "ERROR_LED" : "12" , "CS_LoRa" : "32" , "TX_UART2" : "25" , "TX_UART3" : "14" , "CS_Ethernet__PWR_GSM" : "0" , "SCL_I2C" : "22" , "SCL_OLED" : "4" , "RST_LoRa_Ethe" : "2" , "SDA_I2C" : "21" , "SDA_OLED" : "5" , "DI0_LoRa" : "34" , "RX_UART3" : "17" }

The above configuration will correspond to the board below:

Connect with some componant as ESPrtk standard :

Then , you can connect it to the GNSS RTK modules here:

Connect ESPrtk with RTK Receiver and some other modules.

Note : this board only has 23 GPio Pin , so we cannot add SPI and I2C pin on it , that mean Ethernet and SD Card cannot use on this board !

Attention : The ESP32-PICO chip is currently not supported on version 3.9.x. You should use the chip ESP32-D0W0.
Support for TTGO boards with CHIP PICO is currently only available on version 3.2.5.

For example #2: LILYGO® TTGO LoRa32 V2.1 ESP32 433 MHz / 868 MHz / 915 MHz OLED 0.96 Inch SD Card Bluetooth WIFI Mô-đun SMA IP5306   + Custom Pinmap.

Attention : The ESP32-PICO chip is currently not supported on version 3.9.x. You should use the chip ESP32-D0W0.
Support for TTGO boards with CHIP PICO is currently only available on version 3.2.5.

The JSON code should be : 

(copy all text in box)

{ "CWB_Button" : "36" , "RX_UART0" : "3" , "MOSI_SD_Card" : "15" , "MOSI_LoRa_Ethe" : "27" , "TX_UART0" : "1" , "MISO_SD_Card" : "2" , "MISO_LoRa_Ethe" : "19" , "RX_UART1" : "34" , "SCK_SD_Card" : "14" , "SCK_LoRa_Ethe" : "5" , "TX_UART1" : "4" , "CONNECT_LED" : "17" , "CS_SD_Card" : "13" , "RX_UART2" : "35" , "ERROR_LED" : "25" , "CS_LoRa" : "18" , "TX_UART2" : "12" , "TX_UART3" : "16" , "CS_Ethernet__PWR_GSM" : "0" , "SCL_I2C" : "33" , "SCL_OLED" : "22" , "RST_LoRa_Ethe" : "23" , "SDA_I2C" : "32" , "SDA_OLED" : "21" , "DI0_LoRa" : "26" , "RX_UART3" : "39" }

Attention : The ESP32-PICO chip is currently not supported on version 3.9.x. You should use the chip ESP32-D0W0.
Support for TTGO boards with CHIP PICO is currently only available on version 3.2.5.

The above configuration will correspond to the board below:

Then , you can connect it to the GNSS RTK modules here:

Connect ESPrtk with RTK Receiver and some other modules.

• Make sure you changed Type CHIP ESP32 PICO before using. Go to http://192.168.4.1/system. , Then choose type CHIP ESP32 is ESP32 PICO D4 -> Press Save.
• We cannot using CONNECT_LED and NEOPIXEL_LED on this board !
• An additional piece of aluminum heatsink should be placed on CHIP ESP32 PICO to avoid temperature issues.
• Most GPIO pins (5/18/19/23/26/27) for SPI-LoRa are not connect to external output pins , if you plan to test Ethernet on this board, you need to connect the SPI-Ethernet interface directly with the pins on the LoRa module.
• The CWB Button now change from GPIO13 to GPIO36.
• You should also know: On this board, 2 pins GPIO04 / GPIO12 (for TX_UART1 / 2) are also connected to 2 Data2 / Data3 pins of the SD card slot. In fact, ESPrtk never uses these two Data2 / Data3 pins of a memory card.

Exceptions .

ESPrtk supports changing all output pins. However, not all configurations are accepted.

-Some GPio pins of ESP32 cannot be used for ESPrtk if it does not fully support. See table below 

GPio (ESP32)	…map to ESPrtk ( Input )	.. map to ESPrtk ( Output )
Input-Output	Yes	Yes
Input Only	Yes	No
Output Only	No	Yes

Sometime the configuration is successfully saved (passes the Logic test) but ESPrtk will fail or not work properly, this depends on how the user configures and how ESP32 work with that configuration.

GPIO (ESP32)	Input	Output	Notes
0	pulled up	OK	outputs PWM signal at boot
1	TX pin	OK	debug output at boot
2	OK	OK	connected to on-board LED
3	OK	RX pin	HIGH at boot
4	OK	OK
5	OK	OK	outputs PWM signal at boot
6	x	x	connected to the integrated SPI flash
7	x	x	connected to the integrated SPI flash
8	x	x	connected to the integrated SPI flash
9	x	x	connected to the integrated SPI flash
10	x	x	connected to the integrated SPI flash
11	x	x	connected to the integrated SPI flash
12	OK	OK	boot fail if pulled high
13	OK	OK
14	OK	OK	outputs PWM signal at boot
15	OK	OK	outputs PWM signal at boot
16	OK	OK
17	OK	OK
18	OK	OK
19	OK	OK
21	OK	OK
22	OK	OK
23	OK	OK
25	OK	OK
26	OK	OK
27	OK	OK
32	OK	OK
33	OK	OK
34	OK		input only
35	OK		input only
36	OK		input only
39	OK		input only

Continue reading for a more detail and in-depth analysis of the ESP32 GPIOs and its functions.

Input only pins

GPIOs 34 to 39 are GPIs – input only pins. These pins don’t have internal pull-ups or pull-down resistors. They can’t be used as outputs, so use these pins only as inputs:

• GPIO 34
• GPIO 35
• GPIO 36
• GPIO 39

Introduce ..

This is an advanced feature that allows users to interfere into the output controller by pin mapping on ESP32 to ESPrtk ..

In this way, the selection and placement of the output pins on ESP32 will not depend on the default configuration, making it easier for users to redesign their own ESPrtk PCB board.

This is a system configure and it is hidden when accessed in the Web Configure.
To be able to access this page, after the login Profile, type http://192.168.4.1/system  to enter System page.

This page showing with a black background interface , users can drag and drop ESP32 pins into the frame corresponding to ESPrtk. Click “Save” button to save the configuration.

Or user can enter the JSON string into the text field and click “Save as JSON” to save the configuration.

After that, ESPrtk will check the logic, if there is no error, it will print “Config GPIO save success” in the Submit status box.

At the same time, it export a JSON string, clicks “Copy output” to save it in Clipboard as text and paste it anywhere.

Configure data will store in FLash in ESP32 .

Video

Default config from ESPrtk Factory (JSON):

This is the default configuration on ESPrtk, you may need it to restore to the default configuration state, just Copy it, paste it into the JSON box and click “Save as JSON”.

(Copy all text in box)

{ "CWB_Button" : "13" , "RX_UART0" : "3" , "MOSI_SD_Card" : "23" , "MOSI_LoRa_Ethe" : "33" , "TX_UART0" : "1" , "MISO_SD_Card" : "39" , "MISO_LoRa_Ethe" : "35" , "RX_UART1" : "17" , "SCK_SD_Card" : "18" , "SCK_LoRa_Ethe" : "25" , "TX_UART1" : "5" , "CONNECT_LED" : "15" , "CS_SD_Card" : "19" , "RX_UART2" : "16" , "ERROR_LED" : "12" , "CS_LoRa" : "32" , "TX_UART2" : "4" , "NEOPIXEL_LED" : "14" , "CS_Ethernet" : "0" , "SCL_I2C" : "22" , "SCL_OLED" : "27" , "RST_LoRa_Ethe" : "2" , "SDA_I2C" : "21" , "SDA_OLED" : "26" , "DI0_LoRa" : "34" , "ESPrtk_IO" : "36" }

The above configuration will correspond to the diagram below:

Please read ESPrtk datasheet for detail information about pinout on ESPrtk.

• ESPrtk datasheet and documents
• Connect ESPrtk to RTK receiver and some other modules

Application .

Besides helping make PCB design more flexible, this feature allows ESPrtk to be compatible on all hardware boards with different pinout designs.

For example #1: WEMOS / Lolin ESP32 OLED board.

This module is integrated OLED LCD on GPIO5 (SDA_2) and GPIO4 (SCL_2) on board ( ESPrtk also supports OLED display ).

However, by default pin GPIO5 and GPIO4 on ESP32 are TX_UART1 and TX_UART2 of ESPrtk (see default JSON above) so we will swap the configuration on 6 pin, specifically:

• SCL_OLED : from  27   to 4
• SDA_OLED : from  26  to 5
• TX_UART2 : from  4 to 25
• TX_UART1 : from  5 to 26
• RX_UART1 : from  17 to 36
• RX_UART3 : from  36  to 17

And other pins remain the same as default.

The JSON code should be : 

(copy all text in box)

{ "CWB_Button" : "13" , "RX_UART0" : "3" , "MOSI_SD_Card" : "19" , "MOSI_LoRa_Ethe" : "33" , "TX_UART0" : "1" , "MISO_SD_Card" : "39" , "MISO_LoRa_Ethe" : "35" , "RX_UART1" : "36" , "SCK_SD_Card" : "18" , "SCK_LoRa_Ethe" : "27" , "TX_UART1" : "26" , "CONNECT_LED" : "15" , "CS_SD_Card" : "23" , "RX_UART2" : "16" , "ERROR_LED" : "12" , "CS_LoRa" : "32" , "TX_UART2" : "25" , "NEOPIXEL_LED" : "14" , "CS_Ethernet" : "0" , "SCL_I2C" : "22" , "SCL_OLED" : "4" , "RST_LoRa_Ethe" : "2" , "SDA_I2C" : "21" , "SDA_OLED" : "5" , "DI0_LoRa" : "34" , "ESPrtk_IO" : "17" }

The above configuration will correspond to the board below:

Connect with some componant as ESPrtk standard :

Then , you can connect it to the GNSS RTK modules here:

Connect ESPrtk with RTK Receiver and some other modules.

Note : this board only has 23 GPio Pin , so we cannot add SPI and I2C pin on it , that mean Ethernet and SD Card cannot use on this board !

For example #2: LILYGO® TTGO LoRa32 V2.1 ESP32 433 MHz / 868 MHz / 915 MHz OLED 0.96 Inch SD Card Bluetooth WIFI Mô-đun SMA IP5306   + Custom Pinmap.

The JSON code should be : 

(copy all text in box)

{ "CWB_Button" : "36" , "RX_UART0" : "3" , "MOSI_SD_Card" : "15" , "MOSI_LoRa_Ethe" : "27" , "TX_UART0" : "1" , "MISO_SD_Card" : "2" , "MISO_LoRa_Ethe" : "19" , "RX_UART1" : "34" , "SCK_SD_Card" : "14" , "SCK_LoRa_Ethe" : "5" , "TX_UART1" : "4" , "CONNECT_LED" : "17" , "CS_SD_Card" : "13" , "RX_UART2" : "35" , "ERROR_LED" : "25" , "CS_LoRa" : "18" , "TX_UART2" : "12" , "NEOPIXEL_LED" : "16" , "CS_Ethernet" : "0" , "SCL_I2C" : "33" , "SCL_OLED" : "22" , "RST_LoRa_Ethe" : "23" , "SDA_I2C" : "32" , "SDA_OLED" : "21" , "DI0_LoRa" : "26" , "ESPrtk_IO" : "39" }

The above configuration will correspond to the board below:

Then , you can connect it to the GNSS RTK modules here:

Connect ESPrtk with RTK Receiver and some other modules.

• Make sure you changed Type CHIP ESP32 PICO before using. Go to http://192.168.4.1/system. , Then choose type CHIP ESP32 is ESP32 PICO D4 -> Press Save.
• We cannot using CONNECT_LED and NEOPIXEL_LED on this board !
• An additional piece of aluminum heatsink should be placed on CHIP ESP32 PICO to avoid temperature issues.
• Most GPIO pins (5/18/19/23/26/27) for SPI-LoRa are not connect to external output pins , if you plan to test Ethernet on this board, you need to connect the SPI-Ethernet interface directly with the pins on the LoRa module.
• The CWB Button now change from GPIO13 to GPIO36.
• You should also know: On this board, 2 pins GPIO04 / GPIO12 (for TX_UART1 / 2) are also connected to 2 Data2 / Data3 pins of the SD card slot. In fact, ESPrtk never uses these two Data2 / Data3 pins of a memory card.

Exceptions .

ESPrtk supports changing all output pins. However, not all configurations are accepted.

-Some GPio pins of ESP32 cannot be used for ESPrtk if it does not fully support. See table below 

GPio (ESP32)	…map to ESPrtk ( Input )	.. map to ESPrtk ( Output )
Input-Output	Yes	Yes
Input Only	Yes	No
Output Only	No	Yes

Sometime the configuration is successfully saved (passes the Logic test) but ESPrtk will fail or not work properly, this depends on how the user configures and how ESP32 work with that configuration.

GPIO (ESP32)	Input	Output	Notes
0	pulled up	OK	outputs PWM signal at boot
1	TX pin	OK	debug output at boot
2	OK	OK	connected to on-board LED
3	OK	RX pin	HIGH at boot
4	OK	OK
5	OK	OK	outputs PWM signal at boot
6	x	x	connected to the integrated SPI flash
7	x	x	connected to the integrated SPI flash
8	x	x	connected to the integrated SPI flash
9	x	x	connected to the integrated SPI flash
10	x	x	connected to the integrated SPI flash
11	x	x	connected to the integrated SPI flash
12	OK	OK	boot fail if pulled high
13	OK	OK
14	OK	OK	outputs PWM signal at boot
15	OK	OK	outputs PWM signal at boot
16	OK	OK
17	OK	OK
18	OK	OK
19	OK	OK
21	OK	OK
22	OK	OK
23	OK	OK
25	OK	OK
26	OK	OK
27	OK	OK
32	OK	OK
33	OK	OK
34	OK		input only
35	OK		input only
36	OK		input only
39	OK		input only

Continue reading for a more detail and in-depth analysis of the ESP32 GPIOs and its functions.

Input only pins

GPIOs 34 to 39 are GPIs – input only pins. These pins don’t have internal pull-ups or pull-down resistors. They can’t be used as outputs, so use these pins only as inputs:

• GPIO 34
• GPIO 35
• GPIO 36
• GPIO 39