After the genuine BPills the GD32F103 BPills came. GD is not a clone of STM32 - it is a different chip. GD32 BPills came in fall 2015.
Recently the new CKS32 BPills appear. It could be those CKS are re-branded GD32.
You raise some interesting points ...
From
https://smdprutser.nl/blog/stm32f103-vs-gd32f103/----------------------------------------------------------------------------------
The GD32F103C8, manufactured by Gigadevice, has similar specifications and thus many people think the chip is a cloned version of the STM32 part. The chip appears to be the same from a programmers point of view as almost all registers and peripherals are the same. Major differences are the execution speed and flash size. The chip is capable of running a much higher clock frequency (108MHz) and have less wait states for flashrom then the ST counterpart. The size of the flash memory goes up to 3076KB, compared to the 1024KB ST offers.
The differences can be explained by the decapping pictures (done by Zeptobars). The chip appears to consist of two dies: one microcontroller die and a separate flash die. They seem to use just one large single design and a varying size flash chip to serve the whole GD32F103 range. On the controller die there is 128KB SRAM caching the flashrom. This explains the 0 wait states for flash access. This is a similar way the ESP8266 runs (albeit the flash is user replaceable
). Not very surprising as Gigadevice is a big Chinese flash company. Some tweaks to silicon will allow a higher clockspeed (108MHz) and some people report it being 50% faster then the ST part.
Sounds to good to be true! Not very much is found on the internet about this chip, except some people report that not everything is working exactly the same as the STM32
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I have the GD32F103C8 datasheet, that's easy to find.
But
no SVD anywhere, does anyone have a GD32F103.SVD or a link ? (to do comparisons of peripherals, registers and bitfields with the STM32F103).
Re CKS32F103C8T6:
I can't find any info on the CKS32F103C8T6 anywhere on the net, and even "CKS" doesn't list this chip in their products section.
http://www.cksic.com/en/about/217.html"China Key System Co., Ltd. (CKS) is a Chinesetechnology company headquartered in Wuxi, Jiangsu province, that designs,develops and manufactures very-large-scale integrated circuits. It was founded in 2008."
Perhaps the "CKS32F103C8T6" is a re-branded "GD32F103C8" as you say ?