Where to buy 128K st-links?

Peter Lebbing peter at digitalbrains.com
Sun Dec 23 17:40:50 CET 2018


First of all, Pablo, thanks for the interesting link :-).

On 23/12/2018 16:55, Mike Tsao wrote:
> They're all 128K. See
> https://wiki.stm32duino.com/index.php?title=Blue_Pill for one
> discussion. 

The blog post mentions the chip is a STM32F101CBT6. Note the one instead
of a three. But it goes on to mention others had found out they might
well just be a 103 on the inside.

Even though the mentioned 101 is advertised as having 128 KiB flash, it
is advertised as having 16 KiB of RAM instead of the 103's 20 KiB. Now,
it might be this is again untrue, but it might lead to trouble if it
really ends at 16 KiB.

I just looked at a compile with master,
./configure --vidpid=234b:0000 --target=ST_DONGLE --enable-factory-reset --enable-certdo
and the heap starts at just over 10 KiB. That means you can allocate a
bit less than 6 KiB of data before it will crash horribly ;-). I have no
idea how much RAM is allocated on the heap by GnuK, but it could lead to
trouble. Possibly quicker when a reGNUal is attempted...

It would be interesting to confirm some RAM sizes on some of these
devices. Not by looking at configuration registers, but by just writing
and reading data (mind any aliasing of addresses, though).

My 2 cents,


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