So far we have simulated a candle in our Advent calendar and trilled Christmas carols, and in the last week we have also sent pictures to our small display and played a slide show. An external EEPROM memory chip and a diode will be added this Advent Sunday.
With the additional memory we can then store multiple images at the same time. The storage capacity of the EEPROM of type 24C512 with I2C-Interface is 512 kBits or 64 kBytes. It can be plugged directly into the breadboard through the DIP8 housing. The I2C address is
0xA0. Then we add a font and set the font size that we like best.
The breadboard construction
The EEPROM (IC1) is connected to the I via pins SDA and SCL2C-bus connected. The supply voltage is – as for all other circuit parts – 5 volts. The WP pin is connected to GND so that write access is possible. The address pins A0 to A2 are also connected to GND so that the I2C-Address
The VCC pin is connected to 5V via the diode D1: This little trick ensures that the supply voltage for the EEPROM is one diode forward voltage less than 5 volts, as the minimum voltage for detecting a HIGH level at SDA and SCL 0.7 * VCC is. With a supply voltage of 5 volts this is 3.5 volts. Otherwise, it could be that a HIGH level is not reliably detected, since we only switched the pull-up resistors integrated on the OLED module to 3.3 volts last week.
Four little doors instead of 24: With the Nano-Ax-Board we are building a glowing and sounding project for four Advent Sundays to participate.
The EEPROM is plugged into sockets E23 (IC Pin 1) to E26 (IC Pin 4) and F23 (IC Pin 8) to F26 (IC Pin 5) in the middle on the right so that the notch on the IC points towards the Nano-Ax-Board . In the Fritzing sketch, the EEPROM, the diode and the eight wires in the colors white (SDA), yellow (SCL) and blue (GND) have been added to the EEPROM.