Voltage Divider provided on A0 to measure VIN ( to be safe, we calculated the resistors for 22v)ĥ). 8 Analog Inputs ( While practically you can only use 6 of these if you use I2C )Ĥ). There are also 3x 3.3V I2C Headers, complete with 3.3v and Ground, as well as a single 5v I2C headerģ). and the ESP8266 on the Motherboard is a 3.3v device. Dedicated LDO Regulators for 5v and 3.3v (800mA each), with jumpers to switch them on or off (receive power only from the IoT Motherboard).Ģ.) Dedicated Logic Level Converter on the I2C Bus ( This is sort of very much needed 🙂 The Atmega 328P-AU is running at 5v on this device, to enable it to run at 16Mhz. Some Features (Aside from being a fully functional Arduino clone as well)ġ). MCU-8266-12E with Arduino Nano (left) and MCU-8266-12E with the newly designed APE Card (right) The beginning of the APE (Arduino Port Extender) Device. They used a standard Arduino board for that, but we decided that, after testing it with an Arduino Nano, since it seems to work well, let us just design a dedicated PCB.

While looking at various ideas for this card, the most flexible seemed to be the APE Protocol device as documented in ESPHome. Granted that you do have access to unused pins on the PCF8574 Port Extender, We nonetheless decided that an add-on card would definitely make sense to allow this device to really be more useable. While the baseboard already has quite a lot of free GPIO pins for additional sensors and devices, It did however have quite a few issues, namely a lack of sufficient Power outputs, difficulty access to the I2C bus, as well as only 2 relay outputs.

Port Extender Card for the MCU-8266-12E IoT ControllerĪfter quite a few experiments, and playing with a lot of ideas, we have finally produced and tested an almost final prototype for the MCU-8266-12E IoT Controller Port Extender Card.

Esphome raspberry pi zero