hi community,
I have an D1 mini (ESP8266) board, which reads temperature and humidity from a SHT31 sensor and transfer it to an Raspberry Pi via MQTT using wifi. For debug purpose, It also prints messages like temperature via serial interface. --> works good and stable!
Now I want to expand the configuration to be able to read serial messages from a PV-power converter. For that purpose i bought some Max3232 boards like that: ARCELI 5pcs MAX3232 Root-Modul-Anschluss-Chip zu TTL-Buchse serieller Port zu TTL DB9-Konverter-Modulplatine passend für Ausrüstungs-Upgrades wie DVD : Amazon.de: Elektronik & Foto.
The max3232 ist connected to RX, TX, GND and 3.3V of the D1 mini. In a first step, i'd like to make sure, that the hardware works as expected. So i interface the other side of the max232 to a USB-serial adapter and plugged it into the my notebook. in Hterm I receive some jumble lines (like wrong baud, but not the expected messages. However, baud is correct (9600). (8N1)
What can be the reason for the unexpected behavior?
Some configurations I have tried:
--------- -----------
| | | D1 |
| Note- |USB ---USB| mini |
| book | | ESP8266 |
| | | |
---------- -----------
--> Serial-Monitor output as expected
--------- ------------ -----------
| | | USB |RX-----TX| D1 |
| Note- |USB ---USB| serial |TX ----RX| mini |USB---- USB-Power-Bank
| book | | converter |GND---GND| ESP8266 |
| | | | | |
---------- ------------- -----------
--> Hterm output as expected --> USB-Serial-converter works. Hterm-config seems correct
--------- ------------ ----------- ---------
| | | USB |RX-----TX| |RX ------TX| D1 |
| Note- |USB ---USB| serial |TX ----RX| MAX3232 |TX-------RX| mini | USB---- USB-Power-Bank
| book | | converter |GND---GND| |GND-----GND| ESP8266 |
| | | | | |VIN----3.3V| |
---------- ------------- ----------- -----------
--> Hterm output jumble (MAX3232 may damage(?) --> 2nd Max tried, same result
--------- ------------ ----------- ---------
| | | USB |RX-----TX| |RX-| | D1 |
| Note- |USB ---USB| serial |TX ----RX| MAX3232 |TX-| | mini | USB---- USB-Power-Bank
| book | | converter |GND---GND| |GND-----GND| ESP8266 |
| | | | | |VIN----3.3V| |
---------- ------------- ----------- -----------
--> MAX3232 RX-TX connected (loop). Sending lines via Hterm results in the expected return (same as sent). ---> Max seems to be ok.
What else can be the reason, that I don't receive the expected lines from ESP via MAX3232 and serial converter?
Thx in advance 