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I bought FTDI’s TTL-232R-3V3 to USB Serial Converter cable to program my ESP32 board

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When I decided to put the flip flop circuit to connect ESP32 reset & boot0 pins to DTR & RTS pin, I suddenly found this cable only has CTS & RTS pin my question is should DTR be connected to CTS or I should use the capacitor and connected to the reset pin which triggers by RTS pin ?

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2 Answers 2

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The FT232R should allow to change the CTS pin from the default input to an output. However, one needs to use the D2XX driver instead of the VCP. This is even already implemented by one: https://github.com/jimparis/esptool-ftdi .

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UART pins DTR and RTS are outputs.

Both outputs are used to control the transistors, which in turn control the ESP32 pins. The transistor circuit also does not form a flip-flop.

CTS pin is an input. It can't be used in place of DTR.

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  • \$\begingroup\$ the flip-flop circuit came from standard dev bord, and yes that's my question: can I use the RTS pin to trigger the DTR with some delay with help of CAP? \$\endgroup\$
    – Hamid s k
    Commented Feb 27, 2022 at 21:38
  • \$\begingroup\$ A flip-flop is a bistable circuit you can store a bit of data, so the circuit used to interface ESPs is not a flip-flop. Hardware-wise, you are free to use RTS, there is no problem, the problem is the software support. Will any program you use to program the ESP use RTS pin instead of DTR? If not, then it can't be used, unless you are willing to modify those programs, assuming their source codes are available. \$\endgroup\$
    – Justme
    Commented Feb 27, 2022 at 21:41

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