There's a lot jam-packed into this shield! Let's take a look at what we've got going on.
- GND - Common power/logic ground.
- 3V - this is the output from the 3.3V regulator. The regulator can supply 500mA peak but half of that is drawn by the ESP32, and it's a fairly power-hungry chip.
- 5V - This is the input to the regulator
- IOr - This is IORef, the IO voltage we will communicate with and is required.
Both ESP32 and SD card use SPI to send and receive data. These pins are labeled CLK MISO MOSI and have level shifting so you can use this shield with 3.3V or 5V microcontroller boards.
By default the 2x3 pin ICSP header on the right hand side is where the SPI signals are found.
Required Control Pins:
Optional Control Pins:
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There's a lot of space available on this shield so we also stuck on a micro SD card holder, great for datalogging or storing data to transmit over WiFi. In addition to the shared SPI pins, the SD (chip select) pin is also used. It can be re-assigned to any pin by cutting the trace underneath the board and rewiring. If the SD card is not used, the SD pin can be used for any other purpose |
There is a small RGB LED to the left of the ESP32. These RGB LEDs are available in the Arduino and CircuitPython libraries if you'd like to PWM them for a visual alert. They're connected to the ESP32's pins 26 (Red), 25 (Green), and 27 (Blue). |
We have a big grid of prototyping holes and power rails if you want to make some custom circuitry! |