Adafruit QT Py CH32V203 flash size wrong

[maxgerhardt]

As per the schematic in https://learn.adafruit.com/adafruit-qt-py-ch32v203?view=all#files-3176409, the board is using a CH32V203G6U6, which has only 32 KB Flash and 10KB RAM.

See https://www.wch.cn/products/CH32V203.html

This core however says it has 224 KB flash and 10KB RAM.

arduino_core_ch32/boards.txt

Lines 527 to 531 in d767162

	#Adafruit QTPy CH32V203G6 Board
	CH32V20x_EVT.menu.pnum.CH32V203G6_ADAFRUIT_QTPY=Adafruit QTPy CH32V203G6
	CH32V20x_EVT.menu.pnum.CH32V203G6_ADAFRUIT_QTPY.node=NODE_V203G6_ADAFRUIT_QTPY
	CH32V20x_EVT.menu.pnum.CH32V203G6_ADAFRUIT_QTPY.upload.maximum_size=229376
	CH32V20x_EVT.menu.pnum.CH32V203G6_ADAFRUIT_QTPY.upload.maximum_data_size=10240

[maxint-rd]

the board is using a CH32V203G6U6, which has only 32 KB Flash and 10KB RAM

From what I've read, that 224KB size isn't wrong. All V203 packages supposedly have a second flash die embedded in the package, next to the MCU. Allthough slower, it is much larger than the flash area of the primary MCU die in the package. The qt-py board definition uses this extra flash area. You can read all about it in this post. Note that using that flash requires wchisp and/or wchlink.

This very interesting blogpost has an elaborate description and includes high resolution pictures of the chips within the package.

[maxgerhardt]

That's.. extremely weird. I will have to test this.

Even commercial boards that I've bought with a e.g. CH32V203C8 have "ROM 64KB" in the description, without the mention of the 224KB extra (or rather, total size it seems). That's huge, and also very weirdly sized given there's only 10 KB SRAM.

[maxint-rd]

Found another interesting post here. It shows a nice X-ray picture, and better even: it seems that the entire 256KB can be used to flash code after erasing the bootloader.