ESP8266 Community Forum

So by reading discussions about the ESP8266 there is a lot of mentioning of UART0 and UART1. Could someone specify these UART's to me since it's hard to find clear information about them.

I'm new to the ESP8266 and I'm currently able to compile a blinky example, and upload the firmware to the chip. This implies my toolchain is correctly installed. The next step is ofcourse to gain some debug information. For this I'm using the os_printf function, but I'm not getting any output on the TX/RX pins of the chip, neither GPIO0 or GPIO2.
It would be very nice if someone could provide me with a minimal example of how to write debug information to any of those UART's provided aswell as describing the pinout I need to use to read this information
.

Hi,

UART1 has only Tx pin and hence is used (wisely) for debug prints.
UART0 has Rx, Tx and flow control pins - hence it is a better to use this to interface ESP8266 to other components of your system.

I too am looking for a simple echo program on the UART0. Can't figure out how to read the UART0 Rx Fifo.

Regards,
Ravi

If you look in the UART include file, you will see there are two sets of I/O ports for the UART.