November 20, 2020

Black Pill boards - notes and links for future work

Maybe should get arm-gdb going on Fedora again?


WFI, WFE, and sleep

The following article is exceptionally good:


Someone is working on a Xinu port to STM32 (The STM32F103 on an STM32-Mini). They show the STM32F103RCT6 as having 48k of SRAM, which is a surprise, but a look at the datasheet shows that there are 3 classes of F103 devices. Here is how to decypher what class device you have. First throw out the "T6" at the end. Now look at the last 2 letters that remain (here "RC"). The last letter (here "C") tells you the class. My Blue pills from China are "C8T6" so the vital letter is "8" which indicates that they are medium density devices with 128K flash and 20K ram as I have always thought. My Leaf Labs "Maple" boards have a "RBT6" as does my Olimexino. The "B" is the same as the "8" in indicating a medium density device. However the "Mini" has an "RCT6" and the "C" indicates a high density device. There are several high density F103 devices, this one has 256K of flash and 48K of SRAM.

i2c and usb

Feedback? Questions? Drop me a line!

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