External LED on GPIO16

[twam]

The Feature

GPIO16 (U2RXD) seems unused in the ESP-CAM schematic. Would it be possible to add an optional to use this for a flash?

I have a LED ring light with a low-active EN, which would require an unused GPIO in open-drain configuration (preferred) or push-pull.

PS:
The current GPIO settings only support GPIO4 and GPIO12. However it looks like I cannot assign GPIO12 to an external flash as suggested in the paragraph before.

[caco3]

not sure if pin 16 really is unused (UART). But it should be possible to extend the other pins as open drain or inverted output.

[twam]

From my understanding UART0 on GPIO1 and GPIO3 is used.

GPIO4/GPIO12 seem used for SD-Card as well, or?

[twam]

Meh – double check the schematic. GPIO16 Is actually used as a chip-select for the PSRAM – It has two names in the schematic (IO16 and U2RXD).