Added 74880 baud rate to the serial monitor.

[Chris--A]

Now that the latest IDE incorporates a board/core manager, the
ESP8266 community is now using this software. The baud rate of 74880
is important for debugging as it is what the bootloader uses.

[matthijskooijman]

That's not a standard baudrate, I think? What protocol does the FTDI chip use? CDC ACM like the Uno r3, or is there an FTDI chip on there?

I ask because on Linux, non-standard baudrates are tricky (to the point of not working at all using CDC ACM, see https://github.com/arduino/Arduino/issues/3351#issuecomment-113873045https://github.com/arduino/Arduino/issues/3351#issuecomment-113873045).

[Chris--A]

The board I use to communicate with the ESP8266 (ESP-12) is a basic FT232RL module. I'm guessing CDC however its whatever the windows built in driver uses. I'll have a look later on and see if I can find any information.

However this baud rate is the default used on all ESP8266 chips.

[matthijskooijman]

No, the FTDI modules use a different protocol than CDC devices. Both are supported on Windows and Linux, but the Linux FTDI driver supports the API that the IDE uses (through the JSSC library) to set custom baudrates.

[Testato]

the ESP8266 is a chip with hardware serial at 3,3V level. It is a your choice which serial-usb device use on the project.
NodeMCU board ver0.9 use the CHxxx series, NodeMCU board ver 1.0 usethe CPxxx series. But this is not important.
The 74880 baudrate is directly related to the quartz used on ESP8266, if you use a 40MHz clock the standard baud is 115200, but on all ESP8266 that we have on ebay and other manufacter is used a clock of 26MHz and automatically the baudrate become 74880
So i think it is good add it to SerialMonitor speed selection

[cmaglie]

Looks like this baud rate is really wanted. So I'm going to merge this even if this is going to work only with FTDI chip.

[PaulStoffregen]

This may have unintended consequences, especially on Linux.

Long ago, the serial monitor had 14400 and 28800 in the baud rate menu. With /dev/ttyACM0, setting either of those caused a bug in the driver to lock up the device. Thereafter, the serial monitor couldn't properly open the port, which made it impossible to change to a working baud rate.

Hopefully we won't see that on modern Linux and JSSC. I can tell you it was a big problem, years ago, with older kernels and RXTX.

[cmaglie]

@PaulStoffregen
I've tried to set the 74880 back and forth, my ttyACM0 is not able to set it (it keep the previously set speed) but there are no other side effect, I can change the speed back to another value.

BTW your comment makes me thing that we can actually get an error value from JSSC that tell us if the baudrate change has been successful or not. I'll check this out.

[cmaglie]

Here we go: #3420

It seems to be working, at least for me, when I try to set 74880 baud the error is printed on the console.

It would be nice if someone can confirm that Linux+ESP (or any other FTDI based converted) instead works.