| Feature | TTL-232R-3V3 (This Guide) | TTL-232R-5V | | :--- | :--- | :--- | | | 3.3 Volts | 5.0 Volts | | VCC Output | 3.3 Volts | 5.0 Volts | | Safe For | 3.3V devices (ESP8266, STM32, RPi) | 5V devices (Arduino Uno, Legacy chips) |
| Symptom | Likely Cause | Fix | |---------|--------------|-----| | No device appears | Driver not installed | Reinstall FTDI VCP driver | | Device appears but no data | TX/RX swapped | Swap orange & yellow | | Garbage characters | Baud rate mismatch | Match baud rates exactly | | Can't open port | Another app using it | Close all serial monitors | | Device disappears after a few seconds | Power draw from red wire too high | Use external power for target | | "FTDI FT232R USB UART" with warning in Device Manager | Fake FTDI chip (counterfeit) | Use older FTDI driver (v2.8.14) or buy genuine | ttl232r-3v3 driver
Run the CDM2xxxx_Setup.exe file. This installs both the VCP and D2XX drivers. | Feature | TTL-232R-3V3 (This Guide) | TTL-232R-5V