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I bought the following version of HX711 module.

BOB Front

BOB Back

Connection to Arduino VCC -> 5V GND -> GND SCK/TX -> GPIO 6 DT/RX -> GPIO 7

However, it doesn't work. I have tried different libraries and even different boards but there seems to be communication problem with the module. I assume it has something to do with the mcu chip and the jumper connections J3 & j4. The mcu chip is STC 8F1k08.

There are a lot of tutorials regarding HX711 modules but I couldn't find any info about this particular board with an MCU. There is some info (chinese translation) on the sellers page but doesn't say anything about the jumper config. Product page

I tried to find any relevant info in the MCU datasheet but with my limited knowledge of MCUs it didn't help much. Apparently it's possible to communicate through Serial & I2C with this MCU.

From the datasheet MCU pinout it looks like, J3 connects SCL & Tx, while J4 connects SDA with common ground. I am confused as it seems like mixing I2C with UART.

So can someone please help me solve the communication issue?

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    \$\begingroup\$ The web site documentation says the MCU makes it serial only (default 9600 baud), so any I2C library you use will fail. \$\endgroup\$ Sep 24 at 14:29
  • \$\begingroup\$ I have used this "old" HX711 to uV levels range (with digital average ) ... I don't know this "version", but it seems that you can (if any problem) however remove MCU easily ... \$\endgroup\$
    – Antonio51
    Sep 24 at 14:59
  • \$\begingroup\$ @JackCreasey Most of the libraries I tried, used Serial comm. e.g. this one github.com/bogde/HX711 but it still doesn't work. \$\endgroup\$
    – Zaffresky
    Sep 24 at 15:10
  • \$\begingroup\$ The library you point to is a Synchronous serial driver for the HX711 chip. The board you have wants to send Asynchronous Serial @9600 baud. \$\endgroup\$ Sep 24 at 15:53
  • \$\begingroup\$ I searched for HX711 asynchronous driver but didn't find a library. So if I understand correctly the HX711 communicates via synchronous serial but the MCU chip communicates using the asynchronous serial. Guess I need to write my library to be able to communicate with this module :( \$\endgroup\$
    – Zaffresky
    Sep 24 at 17:46

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