Can DTR be replaced with GPIO0 in this USB to UART auto-program circuit?

Question

These auto-program circuits have been popular for a long time. They replace the need to press boot and reset physically to put the MCU into programming mode.

Some USB to UART converters do not have a DTR pin, but do have GPIOs that can be programmed with alternate functions.

From the datasheet:

DTR: Data Terminal Ready control output (active low). Note that this pin may toggle when opening a COM port on some operating systems.

GPIO: The pins can be made push-pull to drive external circuitry like LEDs. In addition, the state of these pins can be configured during standard operation, during Suspend, and immediately following reset.

Considering that the transistor-based circuit just needs both to be low to enter programming-mode, can DTR be replaced by a GPIO (on the CP2102N side)?

CP2102 does not exist in QFN20. If yoy mean CP2102N which is a completely different chip then edit your post. A link to a datasheet would have made this clear too. — Justme, Mar 12 '22 at 12:11

score 1 · Answer 1 · answered Mar 11 '22 at 20:09

1

Yes, you can replace DTR with GPIO. You'll need to modify the firmware uploader to use that GPIO pin, though.

answered Mar 11 '22 at 20:09

Kuba hasn't forgotten Monica

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Can DTR be replaced with GPIO0 in this USB to UART auto-program circuit?

1 Answers1