Comparison for Espressif MCUs

Figure 1: A bunch of ESP8266 and ESP32-S2 modules.

Recently Espressif has dramatically reduced release cycles for its microcontrollers, announcing 3 new models in the last 6 months. This without sacrificing innovation, coming to present the first microcontroller with support for 802.11ax (Wi-Fi 6), namely ESP32-C6.

Given the explosion of microcontrollers, I think I have do some tidying up with a comparison table, which can be found below and at the following link on Github. Unfortunately the table is not complete because the complete datasheets have not yet been released for the last 2 announced MCUs (ESP32-S3 and ESP32-C6). It will be updated as soon as all information is made available.

In the table I have reported all the models released by Espressif, namely ESP8266, ESP32, ESP32-S2, ESP32-C3, ESP32-S3, and the latest ESP32-C6. Obviously the comparison with the latest arrivals is merciless (actually 7 years have passed since its release), but it can be useful to understand in practice the improvements that have occurred between the various releases.

Anyway, you will notice that with the last 2 releases Espressif has finally divided its processors into 2 macro groups. The first group includes high-end microprocessors, for devices that don't have to tradeoff, while the second group includes cheaper ones, with fewer features but benefiting from Wi-Fi and Bluetooth connectivity like their full-grown couterparts.

Furthermore, Espressif has recently released ESP Product Selector, a service to compare all available models in all their variations and revisions. Unfortunately it is possible to compare only 3 models at a time, and some information that could be relevant, such as DMA and timer available, is not shown, so for a faster and more effective overview I recommend this table.

Tabella 1: Comparison of Espressif microcontroller families.
	ESP8266	ESP32	ESP32-S2	ESP32-S3	ESP32-C3	ESP32-C6
Announcement Date	2014, August	2016, September	2019, September	2020, December	2020, November	2021, April
Main processor	Tensilica L106 32-bit (up to 160MHz)	Tensilica Xtensa 32-bit LX6 (up to 240MHz) (optionally dual core)	Tensilica Xtensa 32-bit LX7 (up to 240MHz)	Tensilica Xtensa 32-bit LX7 dual core (up to 240MHz)	RISC-V 32-bit (up to 160MHz)	RISC-V 32-bit (up to 160MHz)
SRAM	160KB	520KB	320KB	512KB	400KB	400KB
ROM	0	448KB	128KB	384KB	384KB	384KB
JTAG	X	✓	✓	?	✓	✓
Cache	32 KB instruction	64KB	8/16KB (configurable)	?	16KB	?
WiFi	Wi-Fi 4 (only up to 72.2Mbps)	Wi-Fi 4	Wi-Fi 4	Wi-Fi 4	Wi-Fi 4	Wi-Fi 6
Bluetooth	X	BLE 4.2 (upgrade to 5.0, with limitations)	X	BLE 5.0	BLE 5.0	BLE 5.0
Ethernet	X	✓	X	?	X	?
RTC memory	768B	16KB	16KB	16KB	8KB	?
PMU	✓	✓	✓	?	✓	?
ULP coprocessor	X	✓	ULP-RISC-V	?	X	?
Cryptographic Accelerator	X	SHA, RSA, AES, RNG	SHA, RSA, AES, RNG, HMAC, Digital Signature	SHA, RSA, AES, RNG, HMAC, Digital Signature	SHA, RSA, AES, RNG, HMAC, Digital Signature	SHA, RSA, AES, RNG, HMAC, Digital Signature
Secure boot	X	✓	✓	✓	✓	✓
Flash encryption	X	✓	XTS-AES-128/256	✓	XTS-AES-128	XTS-AES-128
SPI	2	4	4	?	3	?
I2C	1	2	2	?	1	?
I2S	1	2	1	?	1	?
UART	2 (one TX only)	3	2	?	2	?
SDIO Host	0	1	0	2	0	0
SDIO Slave	0	1	0	0	0	0
GPIO	17	34	43	44	22	22
LED PWM	5	16	8	?	6	?
MCPWM	0	6	0	2	0	0
Pulse counter	0	8	4	?	0	X
GDMA*	0	0	0	?	6	?
USB	X	X	USB OTG 1.1	?	Serial/JTAG	?
TWAI**	0	1	1	?	1	?
ADC	1x 10-bit SAR	2x 12-bit SAR, up to 18 channels	2x 13-bit SAR, up to 20 channels	?	2x 12-bit SAR, up to 6 channels	?
DAC	X	2x 8-bit	2x 8-bit	?	X	X
RMT	1x transmission + 1x reception	8x transmission/reception	4x transmission/reception	?	2x transmission + 2x reception	?
Timer	2x 23-bit***	4x 64-bit	4x 64-bit	?	2x 54-bit + 1x 52-bit	?
Temperature Sensor	✓	✓	✓	?	✓	?
Hall Sensor	X	✓	X	?	X	?
Touch Sensor	0	10	14	?	X	?

* All the MCUs have some sort of DMA. However, if this field is not checked, it means that the user hasn't the direct control over DMA. With General DMA term, Espressif intends a specific DMA peripheral in full control of user. He will be responsible to manage such peripheral.

** In some old datasheet and documentation, it was referred as CAN bus.

*** A timer is dedicated to Wi-Fi, so you cannot freely use it.

The table will be updated as new information will be released. Contributions and suggestions are welcomed!

Bibliography and other documents

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