update docs

Author: ThomasFarstrike

docs/os-development/emulating-esp32-on-desktop.md

@@ -21,15 +21,19 @@ To this end, we're using the amazing a159x36 QEMU emulator, which can emulate th
 
 To get it running, follow these steps:
 
-1. Compile QEMU (or get a precompiled build)
+1. Compile the ESP32 QEMU
 2. Pad a MicroPythonOS release image to 16MB (otherwise QEMU refuses it)
 3. Start QEMU with the padded MicroPython release image
 
+There are also [GitHub workflows](https://github.com/MicroPythonOS/qemu/tree/esp-develop-9.2/.github/workflows) that compile the ESP32 QEMU for Linux, Windows, MacOS (intel) and MacOS (arm) so you might be able to download a prebuilt version from the [GitHub actions](https://github.com/MicroPythonOS/qemu/actions) artifacts. You need to be logged in to download them.
+
 ## 1. Compile QEMU
 
 Get the prerequisites:
 
-`sudo apt-get install -y -q --no-install-recommends build-essential libgcrypt-dev libglib2.0-dev libpixman-1-dev libsdl2-dev libslirp-dev ninja-build python3-pip libvte-2.91-dev wget zlib1g-dev`
+```
+sudo apt-get install -y -q --no-install-recommends build-essential libgcrypt-dev libglib2.0-dev libpixman-1-dev libsdl2-dev libslirp-dev ninja-build python3-pip libvte-2.91-dev wget zlib1g-dev
+```
 
 Clone it:
 
@@ -40,7 +44,9 @@ cd qemu
 
 Configure it:
 
-`./configure --target-list=xtensa-softmmu --enable-gcrypt --enable-slirp --enable-debug --enable-vte --enable-stack-protector`
+```
+./configure --target-list=xtensa-softmmu --enable-gcrypt --enable-slirp --enable-debug --enable-vte --enable-stack-protector
+```
 
 Compile it:
 
@@ -50,9 +56,13 @@ Compile it:
 
 Download the [latest release](https://github.com/MicroPythonOS/MicroPythonOS/releases) or use one you built yourself.
 
-A simple way to pad a file to 16MB on Linux is:
+The ESP32 QEMU refuses it if it's not a supported size (2, 4, 8 or 16MB) so just pad it with zeroes.
 
-`dd if=MicroPythonOS_esp32_0.8.0.bin of=MicroPythonOS_esp32_0.8.0.bin.padded bs=1M count=16 oflag=append conv=notrunc`
+A simple way to do this on Linux is:
+
+```
+dd if=MicroPythonOS_esp32_0.8.0.bin of=MicroPythonOS_esp32_0.8.0.bin.padded bs=1M count=16 oflag=append conv=notrunc
+```
 
 ## 3. Start QEMU
 
@@ -70,30 +80,31 @@ Also these are forwarded, although currently unused:
 - `127.0.0.1:10080 to 192.168.4.15:80` when the ESP32 is in Station (WiFi client) mode
 - `127.0.0.1:10081 to 192.168.4.1:80` when the ESP32 is in Access Point (Hotspot) mode
 
-**Note**: QEMU will only log to stdout if you start it from a normal shell, with stdin set. If you're starting it from a script or other tool, consider adding "unbuffer" as a prefix to make sure stdin is set, otherwise you won't see much logging.
+**Note**: QEMU will only log to stdout if you start it from a normal shell because then stdin is be set. If you're starting it from a script or other tool that doesn't set stdin, consider adding the `unbuffer` tool as a prefix at the start of the command to make sure stdin is set, otherwise you won't see much logging.
 
 ## Controls
 
 To navigate around in the emulated T-Display S3:
 
-- press "r" for the reset button
-- press "1" for the GPIO0 button - "previous"
-- press "2" for the GPIO14 button - "next"
+- press `r` for the reset button
+- press `1` for the GPIO0 button - mapped to the "previous" action
+- press `2` for the GPIO14 button - mapped to the "next" action
 - press both for the "enter" action
-- long press "1" for the "back" action
+- long press `1` for the "back" action
 
 You can also click the buttons on the picture of the board if you like.
 
-Also, currently unused but:
+Also, currently unused:
+
 - 7, 8, 9 and 0 are bound to capacitive touch input pins 0, 1, 11 and 12 which correspond to GPIO01, GPIO02, GPIO12 and GPIO13
 
 The code for these controls is in QEMU's `hw/xtensa/esp32s3.c` and `hw/display/st7789v.c`.
 
 ## Building an image with a filesystem
 
-For quick development, rather than doing a full rebuild, you could also just rebuild the filesystem based on internal_filesystem/ and bundle that filesystem in an image.
+For quick development, rather than doing a full rebuild, you could also just rebuild the filesystem based on `internal_filesystem/` and bundle that as a LittleFS2 filesystem in the image.
 
-Run `scripts/make_image.sh` from the [MicroPythonOS repo](https://github.com/MicroPythonOS/MicroPythonOS) to do so.
+Run `./scripts/make_image.sh` from the [MicroPythonOS repo](https://github.com/MicroPythonOS/MicroPythonOS) to do so.
 
-It will call `scripts/mklittlefs.sh` to build the filesystem and bundle it with all the other requisites, giving you a bootable image in one second.
+It will call `./scripts/mklittlefs.sh` to build the filesystem and bundle it with all the other requisites, giving you a bootable image in one second.