mention the erratas and u8g2 in the api docs for i2c and Mini_SSD1306

tenbaht · tenbaht · commit 56b7cf3426b6 · 2018-11-20T14:18:19.000+01:00
diff --git a/docs/api/I2C.md b/docs/api/I2C.md
@@ -124,3 +124,12 @@ topic is the
 Downloading from the ST website requires a (free) registration. Somebody
 uploaded the full package to github:
 https://github.com/jiaohaitao/stsw-stm8004
+
+There are some important notes on I2C implementation in the errata sheets:
+
+- [STM8S001J3/003xx/103xx/903xx Errata sheet, rev. 5
+  (CD00265449)](https://www.st.com/content/ccc/resource/technical/document/errata_sheet/c9/f9/ef/bf/63/91/4a/1f/CD00265449.pdf/files/CD00265449.pdf/jcr:content/translations/en.CD00265449.pdf)
+- [STM8S005xx STM8S105xx Errata sheet, rev. 7
+  (CD00270741)](https://www.st.com/content/ccc/resource/technical/document/errata_sheet/e3/c3/4e/24/0c/ca/4b/e7/CD00270741.pdf/files/CD00270741.pdf/jcr:content/translations/en.CD00270741.pdf)
+- [STM8S007xx STM8S20xxx Errata sheet, rev. 6
+  (CD00244749)](https://www.st.com/content/ccc/resource/technical/document/errata_sheet/7a/94/8f/fe/84/14/41/6d/CD00244749.pdf/files/CD00244749.pdf/jcr:content/translations/en.CD00244749.pdf)
diff --git a/docs/api/Mini_SSD1306.md b/docs/api/Mini_SSD1306.md
@@ -12,6 +12,21 @@ graphical features are missing.
 The Library only supports I2C communication.
 
 
+## Limitations
+
+This Library uses a full display buffer. For a 128x64 display this requires
+128x64 = 8kbit = 1kB of RAM for the display buffer. Since the STM8S103 has
+only 1kB RAM total, there is no way that this will fit. If you ignore the
+compiler warnings about insufficient RAM, it will still run, but you will
+see a graphical memory dump in the lower part of your display. If you are
+careful not to modify that part of the memory the program still works, but
+is not terribly useful. See the oled-mini example.
+
+The [u8g2](https://github.com/olikraus/u8g2/wiki) library by Oli Kraus is
+able to use less RAM by rendering the image in multiple stripes. This is
+slower, but saves RAM. I am thinking of porting that library, but don't hold
+your breath for it.
+
 
 ## API
 
