Updated architecture.

Author: Frostie314159

src/Architecture.md

@@ -1,27 +1,36 @@
 # Architecture
 
+## Hardware
+
+### General
+Wireless communications on the ESP32 chip are interfaced via an RF (Radio Frequency) [peripheral designed by Riviera-Waves](https://www.ceva-ip.com/press/espressif-licenses-and-deploys-ceva-bluetooth-in-esp32-iot-chip/) (now [Ceva-Waves](https://www.ceva-ip.com/)).
+
+### Diagram
 ```mermaid
 block-beta
     columns 2
-    block:wifi["Wi-Fi"]:1
-        columns 1
-        wifimac["Wi-Fi MAC"]
-        wifibb["Wi-Fi Baseband"]
-    end
-    block:bt["Bluetooth"]:1
-        columns 1
-        btlc["Bluetooth Link Controller"]
-        btbb["Bluetooth Baseband"]
-    end
-    block:rf["Radio frequency"]:2
-        clkgen["Clock generator"]
-        switch["Switch"]
-        balun["Balun"]
-        rfrx["RF receiver"]
-        rftx["RF transmit"]
-    end
+    wifibb["Wi-Fi Baseband"]:1
+    btbb["Bluetooth Baseband"]:1
+    adcs["ADCs"]:1
+    dacs["DACs"]:1
+    rfsynth["RF Synthesizer"]:1
+    rfmixer["RF Mixer"]:1
+    balun["Balun"]:2
+    antenna["Antenna"]:2
 ```
+**NOTE:** This diagram is an "educated" guess. If you know any better or seek someone to blame for incorrectness: [Frostie314159](https://github.com/Frostie314159).
 
-Wireless communications on the ESP32 chip are interfaced via an RF (Radio Frequency) [peripheral designed by Riviera-Waves](https://www.ceva-ip.com/press/espressif-licenses-and-deploys-ceva-bluetooth-in-esp32-iot-chip/) (now [Ceva-Waves](https://www.ceva-ip.com/)).
+### Description
+The air interface on the ESP32 consists of two parts. The first is the RF frontend, which is in charge of everything analog. The second is the basebands, which implement the physical layer for WiFi and Bluetooth. Data is shared between these two, in the form of a digital quadrature signal.
+
+#### Basebands
+As previously stated, the basebands implement the PHY of WiFi and Bluetooth. Each baseband is it's own peripheral and is controlled individually.
+
+#### RF Frontend
+The RF frontend contains a balun, RF synthesizer, RF mixer, RF switch and an analog/digital frontend consisting of two ADCs and two DACs. The reason there are two is, that the ESP32 uses complex/IQ sampling. When a signal arrives from one of the basebands, it passes through the DACs and gets converted to an IQ signal, which then passes through the RF switch and enters the mixer, where it's converted to RF. For receiving it's the whole processes in reverse.
+The purpose of the RF switch is to select between the TX and RX paths inside the chip. It can also be set to bridge TX and RX which is used for calibrating the IQ imbalance caused by manufacturing inaccuracies.
 
-On top of that, software stacks for Wi-Fi, Bluetooth and others can be run.
+## Software
+The hardware on the ESP32 is controlled by proprietary blobs, which are interfaced with through a shallow API.
+### WiFi
+The WiFi peripheral on the ES32 is controlled by two FreeRTOS tasks, one of which handles the MAC and the other one the PHY. They interface with each other through a number of message queues, on top of which an `ioctl`-interface exists. Espressif chose a SoftMAC architecture for the ESP32, with only ACKing implemented in hardware.

src/Glossary.md

@@ -3,6 +3,7 @@
 | Short term  | Meaning | Notes |
 | -- | -- | -- |
 | MAC | Medium Access Control | This is context dependent |
+| PHY | Physical Layer | |
 | RF | Radio frequency | |
 | ISM Band | Industrial Scientific and Medical Band | The frequency band, in which WiFi, BT and IEEE 802.15.4 operate, is the 2.4GHz ISM BAND |
 | WLAN | Wireless Local Area Network | This is defined in IEEE 802.11 |