October 31, 2020

Olimexino-STM32

I got one of these as a "free bonus!!" when I won the bid on three Maple r3 boards on Ebay in October of 2020. Nice seller to throw this in.

The star of the show is the usual STM32F103RBT6. This part has 128K of flash as shown by the "B" in the "RBT6".

Mouser still has 131 of these in stock and sells them for $18.68

Power

The board can be powered by USB, or via 9-30 volts on the barrel jack. This is a wider range than the Maple and they brag about it.

The board consumes about 50 mA.

Battery

There is also a connector for a 3.7 volt Li-ion battery, but take care as to the polarity. The board will always try to keep the battery charged if one is connected, and the board is powered from USB or an external supply. There is no "Charge" jumper like the Maple. There are also no charge indicator LED's.

LED's and buttons

There is what appears to be a red power LED near the barrel connector. Then there are two LED's near the USB connector, green and yellow.

There are two buttons. One near the barrel connector appears to be reset. The other near the USB connector is labeled "BUT" or "BOOT0" on the schematic.

Plug it in

I use a mini-USB cable, and see the following when I plug it into my linux system 
Nov  1 08:58:42 trona kernel: usb 1-1.3: new full-speed USB device number 97 using ehci-pci
Nov  1 08:58:42 trona kernel: usb 1-1.3: New USB device found, idVendor=1eaf, idProduct=0003, bcdDevice= 2.00
Nov  1 08:58:42 trona kernel: usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Nov  1 08:58:42 trona kernel: usb 1-1.3: Product: Maple 003
Nov  1 08:58:42 trona kernel: usb 1-1.3: Manufacturer: LeafLabs
Nov  1 08:58:42 trona kernel: usb 1-1.3: SerialNumber: LLM 003

Nov  1 08:58:44 trona kernel: usb 1-1.3: new full-speed USB device number 98 using ehci-pci
Nov  1 08:58:44 trona kernel: usb 1-1.3: New USB device found, idVendor=1eaf, idProduct=0004, bcdDevice= 2.00
Nov  1 08:58:44 trona kernel: usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Nov  1 08:58:44 trona kernel: usb 1-1.3: Product: Maple R3
Nov  1 08:58:44 trona kernel: usb 1-1.3: Manufacturer: LeafLabs
Nov  1 08:58:44 trona kernel: cdc_acm 1-1.3:1.0: ttyACM0: USB ACM device
Yes it seems to connect twice changing the product number from 3 to 4. My interpretation is that the first connect is the boot loader, which runs briefly, then user code is run, which performs a disconnect and reidentifies itself as a USB serial device.

What I see when I connect the device or press reset it a rapidly blinking green LED for not quite a second, then a slow blinking green LED, then the green LED goes out and a yellow LED begins to blink.

I will note that I also have Maple r5 boards and I see exactly the same LED pattern and USB chatter when I connect them.

Feedback? Questions? Drop me a line!

Tom's Computer Info / tom@mmto.org