Some design notes for an MCU board... Deeply WIP.
- STM32 Cortex M4 with FSMC (possibility: STM32F413ZGT6 for 144-LQFP, STM32F413VGT3 for 100-LQFP, and STM32F413RGT6 for 64-LQFP)
- Extra flash and PSRAM
- WIFI module e.g. ESP32 C3 or ESP32 S3
- 4 motor control ports (EV3 compatible)
- 4 sensor control ports (EV3 compatible)
- Raspberry Pi pin-out connector (enough to communicate with Raspberry pi Zero, does not need full support)
- SD card (SPI interface enough/SDIO nice to have but requires supported MCU)
- Accelerometer (could be external)
- STEMMA QT connector (nice to have)
- Some informative display (nice to have)
- A couple of buttons for interface (nice to have also)
- Lego "compatible" physical shape.
- STM32L4R5VGT6 with 640KB of RAM instead of the external ram versions (but it also supports the FMC/FSMC). And it is cheap, and more available than the previous ones. (Or the subtly better STM32L4R5VIT6)
- The WIFI module with the SD card on one side and the Raspberry Pi connector may not need to be active at the same time.
- The display could be controlled by the WIFI module via AT commands. Other things could be moved to the WIFI module too (the interface buttons, maybe).
- The board would be a Raspberry Pi hat that can work alone. This can be a rev 2 objective, but planning for the space would not hurt.
- Driving external memories with the FSMC, application not AN4761
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STM32 Cortex M4 - May be
- STM32L4P5CGT6
- STM32L4P5CGT6P
- STM32L4Q5CGT6
- STM32L4Q5CGT6P all (48-LQFP with 1MB of flash, and 320KB of RAM).
-
4 motor control ports (EV3 compatible)
-
4 sensor control ports (EV3 compatible)
-
Raspberry Pi pin-out connector (enough to communicate with Raspberry pi Zero, does not need full support)
-
SD card (SPI interface enough/SDIO nice to have but requires supported MCU)
-
Accelerometer (could be external)
-
STEMMA QT connector (nice to have)
-
Some informative display and a couple of LEDs (nice to have)
-
A couple of buttons for interface (nice to have also)
-
Lego "compatible" physical shape.