docs: Provide comparison of key features of ESP32 and ESP32-S2 chips

docs/en/hw-reference/chip-series-comparison.rst

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+***********************
+Chip Series Comparison
+***********************
+
+The comparison below covers key features of chips supported by ESP-IDF. For the full list of features please refer to respective datasheets in Section `Related Documents`_.
+
+.. list-table:: Chip Series Comparison
+   :widths: 20 40 40
+   :header-rows: 1
+
+   * - Feature
+     - ESP32 Series
+     - ESP32-S2 Series
+   * - Launch year
+     - 2016
+     - 2020
+   * - Variants
+     - ESP32-D0WDQ6, ESP32-D0WD, ESP32-D2WD, ESP32-S0WD, ESP32-U4WDH, ESP32-PICO
+     - ESP32-S2, ESP32-S2FH2, ESP32-S2FH4
+   * - Core
+     - Xtensa® dual-core 32-bit LX6 with 600 MIPS (in total); 200 MIPS for ESP32-U4WDH/ESP32-S0WD (single-core variants); 400 MIPS for ESP32-D2WD
+     - Xtensa® single-core 32-bit LX7 with 300 MIPS
+   * - Wi-Fi protocols
+     - 802.11 b/g/n, 2.4 GHz
+     - 802.11 b/g/n, 2.4 GHz
+   * - Bluetooth®
+     - Bluetooth 5.0 and Bluetooth LE
+     - ✖️
+   * - Typical frequency
+     - 240 MHz (160 MHz for ESP32-S0WD, ESP32-D2WD, and ESP32-U4WDH)
+     - 240 MHz
+   * - SRAM
+     - 520 KB
+     - 320 KB
+   * - ROM
+     - 448 KB of ROM for booting and core functions
+     - 128 KB of ROM for booting and core functions
+   * - Flash
+     - Up to 16 MB device, address 11 MB + 248 KB each time
+     - Up to 1 GB device, address 11.5 MB each time
+   * - PSRAM
+     - Up to 16 MB device, address 4 MB each time
+     - Up to 1 GB device, address 11.5 MB each time
+   * - Cache
+     - ✔️ 
+     - ✔️ More functionalities, more modes
+   * - **Peripherals**
+     - 
+     - 
+   * - ADC
+     - Two 12-bit, 18 channels
+     - Two 13-bit, 20 channels
+   * - Temperature sensor
+     - ✖️
+     - 1
+   * - Touch sensor
+     - 10
+     - 14
+   * - Hall sensor
+     - 1
+     - ✖️
+   * - GPIO
+     - 34
+     - 43
+   * - SPI
+     - 4
+     - 4 with more modes
+   * - LCD interface
+     - 1
+     - 1
+   * - UART
+     - 3
+     - 2 :sup:`1`
+   * - I2C
+     - 2
+     - 2
+   * - I2S
+     - 2
+     - 1 :sup:`1`
+   * - Camera interface
+     - 1
+     - 1
+   * - RMT
+     - 8 channels
+     - 4 channels :sup:`1`
+   * - Pulse counter
+     - 8 channels
+     - 4 channels :sup:`1`
+   * - LED PWM
+     - 16 channels
+     - 8 channels :sup:`1`
+   * - USB OTG
+     - ✖️
+     - 1
+   * - TWAI
+     - 1
+     - 1
+   * - SD/SDIO/MMC host controller
+     - 1
+     - ✖️
+   * - SDIO slave controller
+     - 1
+     - ✖️
+   * - Ethernet MAC
+     - 1
+     - ✖️
+   * - ULP
+     - ULP FSM
+     - PicoRV32 core with 8 KB SRAM, ULP FSM with more instructions
+   * - **Security**
+     - 
+     - 
+   * - Secure boot
+     - ✔️
+     - ✔️ Faster and safer
+   * - Flash encryption
+     - ✔️
+     - ✔️ More functionalities (support for PSRAM encryption)
+   * - OTP
+     - 1024-bit
+     - 4096-bit
+   * - AES
+     - ✔️
+     - ✔️ DMA support for ECB, CBC, OFB, CTR, CFB8, CFB128 and GCM
+   * - HASH
+     - SHA-1, SHA-2
+     - SHA-1, SHA-2; DMA support
+   * - RSA
+     - Up to 4096 bits
+     - Up to 4096 bits, improved acceleration options
+   * - RNG
+     - ✔️
+     - ✔️
+   * - HMAC
+     - ✖️
+     - ✔️
+   * - Digital signature
+     - ✖️
+     - ✔️
+   * - XTS
+     - ✖️
+     - ✔️
+   * - **Other**
+     - 
+     - 
+   * - Deep-sleep (ULP sensor-monitored pattern)
+     - 100 μA (when ADC work with a duty cycle of 1%)
+     - 22 μA (when touch sensors work with a duty cycle of 1%)
+   * - Size
+     - QFN 5*5, 6*6
+     - QFN 7*7 
+
+**Note** 1: Reduced chip area
+
+
+Related Documents
+=================
+
+- `ESP32 Datasheet (PDF) <https://espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf>`_
+- ESP32-PICO Datasheets (PDF)
+
+    - `ESP32-PICO-D4 <https://www.espressif.com/sites/default/files/documentation/esp32-pico-d4_datasheet_en.pdf>`_
+    - `ESP32-PICO-V3 <https://www.espressif.com/sites/default/files/documentation/esp32-pico-v3_datasheet_en.pdf>`_
+    - `ESP32-PICO-V3-02 <https://www.espressif.com/sites/default/files/documentation/esp32-pico-v3-02_datasheet_en.pdf>`_
+
+- `ESP32-S2 Datasheet (PDF) <https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf>`_

docs/en/hw-reference/index.rst

@@ -15,3 +15,4 @@
     Previous Versions of Modules and Boards <modules-and-boards-previous>
     Espressif Products Ordering Information (PDF) <http://www.espressif.com/sites/default/files/documentation/espressif_products_ordering_information_en.pdf>
     Regulatory Certificates <https://www.espressif.com/en/certificates>
+    Chip Series Comparison <chip-series-comparison>

docs/zh_CN/hw-reference/chip-series-comparison.rst

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+.. include:: ../../en/hw-reference/chip-series-comparison.rst

docs/zh_CN/hw-reference/index.rst

@@ -15,3 +15,4 @@
     模组与开发板（历史版本）<modules-and-boards-previous>
     乐鑫产品订购信息 (PDF) <http://www.espressif.com/sites/default/files/documentation/espressif_products_ordering_information_cn.pdf>
     乐鑫产品证书 <https://www.espressif.com/zh-hans/certificates>
+    Chip Series Comparison <chip-series-comparison>