Information about the Unexpected Maker Storage Shield for TinyPICO, TinyS3 and ProS3.
The storage shield gives you fast reliable onboard storage as well as removable storage via a Micro SD card slot.
This shield includes:
- 16GB of fast (4bit) eMMC onboard storage
- SPI based Micro SD Card slot for removable storage
- PicoBlade (1.25mm) battery connector to make it easy to connect a battery.
- 1.25mm to 2.0mm converter cable for wider battery support
- Male and female headers
What are the advantages of using eMMC over a Micro SD Card?
The key problem with uSD cards and sockets is they can suffer from stability and disconnection issues due to vibration (fast moving data logging) or being dropped and even knocked. They can also collect dust causing issues and uSD cards will wear over time. They can even come loose for other reasons.
Connecting to them over SPI also means they have high latency and communicate slower than eMMC can, so much slower reads and even slower writes and generally have a higher current consumption when reading/writing.
eMMC solves all of this as it runs at 40Mhz, with 4bit wide data transfers, and therefore much faster read/write speeds. eMMC doesn’t suffer from vibration/movement issues so it’s ideal for being used in situations like fast data logging on a moving vehicle, or bike or plane or boat.
eMMC Typically has a longer life cycle and is better suited for industrial and embedded applications where long-term reliability is critical.
The eMMC is only 16GB – but I can get 128GB Micro SD Cards?
Sure, you can get enormous SD Cards now, but not all sizes are compatible with SPI on an microcontroller board, and a lot of cards max out at 32GB for compatibility reasons.
Cheaper high capacity uSD cards can have compatibility/stability issues and are generally much slower than good quality ones… but the cost of *good quality* high capacity cards are prohibitive.
So the Storage shields gives you both options – use the eMMS for fast, low latency, reliable storage on the go, and the SD card slot for less critical data storage or as a means to get the data off (or on) the eMMC easily.
Board & MCU Compatibility
This shield is fully compatible with the TinyPICO, TinyS3 and ProS3 (or any ESP32/ESP32-S3 boards) as the original ESP32 and the ESP32-S3 come with an SDMMC Host controller peripheral which is required to communicate with the eMMC storage.
The ESP32-S2 and ESP32-C6 do not include an SDMMC Host controller peripheral, so cannot communicate with an eMMC chip, but they can still use the uSD card slot on the shield, so the TinyS2 and TinyC6 have been marked on the pinout card as having limited compatibility.
Powering the shield
The components on the shield are powered by the 3V3 header pin, so if you are connecting this shield to another MCU board, please provide 3V3 to that header pin, or the shield will not work.
Using The Shield
If you are using the Arduino IDE for development, we have an example project to get you started using the eMMC + Micro SD Card slot.
Using the SD Card
If you are wanting to use the SD Card slot in your project, please ensure you set the SPI MI pin as an INPUT_PULL_HIGH or initialising the slot may fail.
For Arduino:
pinMode(MI_PIN, INPUT_PULLUP);
3D Model
You can find a 3D STEP model file for the UM Storage Shield in GitHub.
Where To Buy
Available from Unexpected Maker
PRODUCT CODE SH-STORAGE