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#11
ESP32 / Re: ESPHome issue with UART
Last post by LubOlimex - October 09, 2025, 10:42:09 AMYes, just change:
And it will work fine, connect pin #11 and #13 together (to establish simple echo test) then open serial terminal from Tools -> Serial Monitor and you can send something and you will receive it back after some delay (can be reduced by reducing delay(2000); in the code).
For example, I sent 1234 and this is what I got before during and after transmition:
Edit: If you don't have a wire between #11 and #13 (aka GPIO16 and GPIO32) you won't receive neither Echo nor "Hello..." message!
Code Select
#define RX2_PIN 32 // Receive pin for Serial2
#define TX2_PIN 16 // Transmit pin for Serial2And it will work fine, connect pin #11 and #13 together (to establish simple echo test) then open serial terminal from Tools -> Serial Monitor and you can send something and you will receive it back after some delay (can be reduced by reducing delay(2000); in the code).
For example, I sent 1234 and this is what I got before during and after transmition:
Code Select
Received on Serial2: Hello from ESP32-Gateway Serial2!
Received on Serial2: Echo from USB: 1234
Received on Serial2: Hello from ESP32-Gateway Serial2!
Edit: If you don't have a wire between #11 and #13 (aka GPIO16 and GPIO32) you won't receive neither Echo nor "Hello..." message!
#12
ESP32 / Re: ESPHome issue with UART
Last post by LubOlimex - October 09, 2025, 10:36:32 AMHaha, mystery solved, so this is expected outcome! I made a mistake in the code sorry about that. We wrote above about pin #11 and #13 and in the code I defined GPIO11 and GPIO13 which was the mistake. It should be GPIO16 and GPIO32, my bad I mixed the consequent number of the header and the GPIO number.
I will update the code, test and give you updated code soon.
I will update the code, test and give you updated code soon.
#13
ESP32 / Re: ESPHome issue with UART
Last post by ju - October 09, 2025, 09:55:53 AMThis is the same 1m USB-C (65w rated) cable I use for everything, but I tried with a 30cm USB-A->C with the same result.
I don't do anything, I plug the board and the (continuously repeating) serial output is what I've pasted!
I don't do anything, I plug the board and the (continuously repeating) serial output is what I've pasted!
#14
ESP32 / Re: ESPHome issue with UART
Last post by LubOlimex - October 09, 2025, 08:19:53 AMUntil board resets it works fine, but why does it reset? Is it resetting by itself? If so test with another shorter USB cable and port. Maybe this cable is flawed and doesn't make good contact with the board or doesn't provide enough power.
If you didn't reset it, did you open serial terminal on the COM port of board? Connect GPIO11 and GPIO13 together after you open the terminal and type something to see if it will return echo.
If you didn't reset it, did you open serial terminal on the COM port of board? Connect GPIO11 and GPIO13 together after you open the terminal and type something to see if it will return echo.
#15
ESP32 / Re: ESPHome issue with UART
Last post by ju - October 08, 2025, 09:37:03 PMSorry for the delay, I was only able to test now!
Here's the output on the serial monitor:
So, I don't think it's working as expected, right?
Here's the output on the serial monitor:
Code Select
rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46
rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46
rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46
rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46
rst:0x8 (TG1WDT_SYS_RESET),boot:0x1a (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4744
load:0x40078000,len:15672
load:0x40080400,len:3152
entry 0x4008059c
ESP32-Gateway Serial2 demo starting...
Serial2 initialized on GPets Jul 29 2019 12:21:46
So, I don't think it's working as expected, right?
#16
ESP32 / Re: Nominal/max forward curren...
Last post by LubOlimex - October 07, 2025, 10:30:25 AMAs you can see in the pictures it is BRM-LK10DA solid-state relay (SSR), we are just re-seller. The 25A and 40A versions of the relay are named BRM-LK25DA and BRM-LK40DA.
All variants have control terminal voltage in the 3-32VDC range and control current between 5-20mA.
All variants have output terminal voltage in the 24-480VAC range.
The 10A variant has load current of 10A resistive current of 5A and inductive current 1.5A.
The 25A variant has load current of 25A and resistive current of 12A and inductive current 4A.
The 40A variant has load current of 40A and resistive current of 20A and inductive current 6.5A.
The disconnection current of all variants is under 5mA. Insulation resistance for all is 1000MΩ and on-off time is ≤10ms.
All variants have control terminal voltage in the 3-32VDC range and control current between 5-20mA.
All variants have output terminal voltage in the 24-480VAC range.
The 10A variant has load current of 10A resistive current of 5A and inductive current 1.5A.
The 25A variant has load current of 25A and resistive current of 12A and inductive current 4A.
The 40A variant has load current of 40A and resistive current of 20A and inductive current 6.5A.
The disconnection current of all variants is under 5mA. Insulation resistance for all is 1000MΩ and on-off time is ≤10ms.
#17
ESP32 / Re: ESP3-S3-LiPo battery charg...
Last post by maunope - October 06, 2025, 01:45:03 PMHey!
got it, thanks!
Maurizio
got it, thanks!
Maurizio
#18
ESP32 / Re: ESP3-S3-LiPo battery charg...
Last post by LubOlimex - October 06, 2025, 01:33:14 PMIt was mainly a design change since high current draw could limit down the current output for other peripherals attached to the board.
Another thing is that the battery charger chip might get very hot since 450mA is near the maximum it can provide.
My advice is to keep it as it is. Notice that it is not a problem to use 3000mA 3.7 Li-Po battery without any changes. It will just charge slower if it is severely discharged.
But of course you can also change R4 to smaller resistor in with 0402 size and it will have higher current for charge. My advice is not to go as low as 2.2k, maybe down to 3.3k (which is 300mA of current for charging).
Another thing is that the battery charger chip might get very hot since 450mA is near the maximum it can provide.
My advice is to keep it as it is. Notice that it is not a problem to use 3000mA 3.7 Li-Po battery without any changes. It will just charge slower if it is severely discharged.
But of course you can also change R4 to smaller resistor in with 0402 size and it will have higher current for charge. My advice is not to go as low as 2.2k, maybe down to 3.3k (which is 300mA of current for charging).
#19
ESP32 / ESP3-S3-LiPo battery charge cu...
Last post by maunope - October 06, 2025, 12:50:38 PMHi!
I've noticed the battery charge current of this model is 100mA only, whereas the older ESP32 had a 2.2kohm R4, resulting in 455mA.
I'm using a 3000mA battery, which I understand is larger than the recommended 1400mA one, I was considering paralleling a resistor to R4 to be able to charge it in around 12h insteda of 30.
I understand the risk of messing things up/damaging my devkit, apart form this, is there any specific reason for esp32-s3 running 100mA instead of 455?
thanks in advance!
Maurizio
https://github.com/OLIMEX/ESP32-DevKit-LiPo/tree/master/HARDWARE/ESP32-DevKit-LiPo-Rev.D
https://github.com/OLIMEX/ESP32-S3-DevKit-LiPo/blob/main/HARDWARE/ESP32-S3-DevKit-LiPo_Rev_B/ESP32-S3-DevKit-LiPo_Rev_B.pdf
I've noticed the battery charge current of this model is 100mA only, whereas the older ESP32 had a 2.2kohm R4, resulting in 455mA.
I'm using a 3000mA battery, which I understand is larger than the recommended 1400mA one, I was considering paralleling a resistor to R4 to be able to charge it in around 12h insteda of 30.
I understand the risk of messing things up/damaging my devkit, apart form this, is there any specific reason for esp32-s3 running 100mA instead of 455?
thanks in advance!
Maurizio
https://github.com/OLIMEX/ESP32-DevKit-LiPo/tree/master/HARDWARE/ESP32-DevKit-LiPo-Rev.D
https://github.com/OLIMEX/ESP32-S3-DevKit-LiPo/blob/main/HARDWARE/ESP32-S3-DevKit-LiPo_Rev_B/ESP32-S3-DevKit-LiPo_Rev_B.pdf
#20
A20 / Re: A20 can't boot/start anymo...
Last post by LubOlimex - October 06, 2025, 08:56:47 AMIs PWR_LED "the red light" should not blink, it is power good indicator. When you apply power it should turn on and stay on. If it blinks it is either lose connection, or bad power supply adapter, or there is some hardware damage with the board. Did you provide 5V DC to the power jack? Maybe try with another power adapter to exclude problems with the physical connection or bad power supply.