Support for building and running external apps (#112)

Documentation/external-apps.md

@@ -0,0 +1,18 @@
+# External Apps
+
+## Building
+
+Steps to build:
+
+- Build the main project with `idf.py build` in the root folder of the project
+- Open a terminal at `ExternalApps/${AppName}`
+- The first time, run `./build.sh` (during consecutive runs, you can run `idf.py build`)
+- Find the executable `build/${AppName}.app.elf` and copy it to an SD card.
+
+## Developing apps
+
+Currently, only C is supported. The `TactilityC` project converts Tactility's C++ code into C.
+
+Methods need to be manually exposed to the ELF apps, by editing `TactilityC/Source/TactilityC.cpp`
+
+You can put apps in `Data/config` or `Data/assets` during development, because putting it on an SD card takes more effort.

Documentation/ideas.md

@@ -1,4 +1,5 @@
 # TODOs
+- Loader: Use Timer instead of Thread, and move API to `tt::app::`
 - Gpio: Use Timer instead of Thread
 - I2cScannerThread: Use Timer instead of Thread
 - Bug: I2C Scanner is on M5Stack devices is broken
@@ -21,12 +22,14 @@
 - Commit fix to esp_lvgl_port to have `esp_lvgl_port_disp.c` user driver_data instead of user_data
 - Wifi bug: when pressing disconnect while between `WIFI_EVENT_STA_START` and `IP_EVENT_STA_GOT_IP`, then auto-connect becomes activate again.
 - T-Deck Plus: Create separate board config
+- External app loading: Check version of Tactility and check ESP target hardware, to check for compatibility.
 
 # Core Ideas
 - Support for displays with different DPI. Consider the layer-based system like on Android.
 - If present, use LED to show boot status
 - 2 wire speaker support
 - tt::app::start() and similar functions as proxies for Loader app start/stop/etc.
+- USB implementation to make device act as mass storage device.
 
 # App Ideas
 - System logger