RS-232 Modules are not working with ESP32's
Posted: Fri May 31, 2024 3:42 am
Howdy,
Hello I have two ESP 32 devices and I have successfully connected them to communicate over UARTs using the standard TTL interface with basic dupont jumpers.
I have next taken the same esp32 devices and then instead I have inserted rs422 to TTL adapters and communication continues to flow perfectly.
I've then done the same with rs485 to TTL adapters and all is well also with communication flowing in both directions.
The challenge I'm having now is that I have the same ESP32's but am now using rs232 adapters. There's no communication going whatsoever. , I do see what 'appears' to be line noise...garbled chars like "0xFE', etc.
I have validated and verified that the TTL to RS232 adapters actually work by connecting them with DB9 serial cables to a PC (instead of using a USB cable) and seeing the REPL on both of them with my IDE, Thonny.
I then used the same good cable to connect to esp32s but there's still no communication.
In terms of the physical setup it looks like this:
Each esp32 connects to the RS-232 with TX->TX, RX->RX and shares GND w/the module. Each module is powered independently (also tried sharing the same rail) with 5V rails. I put 14 millamps of current to the modules - I thought maybe there was not enough current to them so I tried various values.
I believe I have enough power going to each of the max 3232 modules as it appears the data sheet says it needs somewhere between 3 to 5 volts and seems like up to 20 mA should be fine.
Not really sure what to try next. Any thoughts?
Hello I have two ESP 32 devices and I have successfully connected them to communicate over UARTs using the standard TTL interface with basic dupont jumpers.
I have next taken the same esp32 devices and then instead I have inserted rs422 to TTL adapters and communication continues to flow perfectly.
I've then done the same with rs485 to TTL adapters and all is well also with communication flowing in both directions.
The challenge I'm having now is that I have the same ESP32's but am now using rs232 adapters. There's no communication going whatsoever. , I do see what 'appears' to be line noise...garbled chars like "0xFE', etc.
I have validated and verified that the TTL to RS232 adapters actually work by connecting them with DB9 serial cables to a PC (instead of using a USB cable) and seeing the REPL on both of them with my IDE, Thonny.
I then used the same good cable to connect to esp32s but there's still no communication.
In terms of the physical setup it looks like this:
Each esp32 connects to the RS-232 with TX->TX, RX->RX and shares GND w/the module. Each module is powered independently (also tried sharing the same rail) with 5V rails. I put 14 millamps of current to the modules - I thought maybe there was not enough current to them so I tried various values.
I believe I have enough power going to each of the max 3232 modules as it appears the data sheet says it needs somewhere between 3 to 5 volts and seems like up to 20 mA should be fine.
Not really sure what to try next. Any thoughts?