ESP8266 Discoveries

[NZ0I]

I've been looking into using I2C on the ESP8266 board from Adafruit. The pins are available, and I2C is supported by the Arduino ESP8266 libraries, but the Arduino libraries currently support only master I2C mode. We would want the ESP8266 to function as slave, so that the ATmega328p can remain master of I2C and control the WiFi device along with all the others. So our choices are: 1) Contribute to the Arduino I2C libraries by adding slave mode support ourselves; 2) Implement communications over the UART using escape characters to let the WiFi device know we are sending commands to it. We might want to start with 2) and then work on 1) later.

There is support in the Arduino ESP8266 libraries for EEPROM-like functionality: it sets aside a portion of flash for holding settable values that need to be retained between power cycles. Pretty cool.

It seems to me that the ESP8266 plus the Si5351 all by themselves could comprise an interesting little Foxoring CW transmitter, capable of operating on any band between 80m and 2m, and configured over WiFi using a smartphone or PC. Its software could even be updated over the air using WiFi, with no need for USB support. But that would be a separate project from the 2-Band ARDF transmitter, since it would not support all the power levels and features needed for a transmitter capable of serving in all ARDF events.