Driver capabilities at a glance:

Networking capable:

Processor ->	iMXRT1062	STM32F7xx	STM32H7xx	ESP32	RP 20404	RP 20404	MSP432E401Y	TMC129x
Board	Teensy 4.x	Nucleo-F756ZG	Nucleo-H743ZI		Pi Pico W	Pi Pico	LaunchPad	LaunchPad
MCU speed MHz	600	216	450	2x240	125	125	120	120
Floating point unit FPU	yes	yes	yes	yes	no	no	yes	yes
Non-volatile storage	Flash1	Flash1	Flash1	Flash1	Flash1	Flash1	EEPROM	EEPROM
Number of axes	up to 5	up to 8	up to 8	3	up to 6	up to 6	up to 6	up to 6
Auto-squared/ganged axes17	yes	yes	no	no	yes	yes	no	no
Variable spindle	yes	yes	yes	yes	yes	yes	yes	yes
Ramped spindle	no	no	no	yes	no	no	yes	yes
Inverted spindle PWM	yes	yes	yes	yes	yes	yes	yes	yes
RC Servo/ESC for spindle13	yes	yes	yes	yes	yes	yes	yes	yes
ModBus spindle14	yes15	no	no	yes	yes	yes	no	no
Spindle at speed	yes	yes	yes	no	no	no	no	no
Spindle sync	yes4	yes	yes	no	no	no	no	no
Closed loop spindle RPM	no	no	no	no	no	no	no	no
Native USB streaming	yes	yes	yes	no	yes	yes	no	no
Bluetooth streaming	no	no	no	yes	yes	yes	no	no
Telnet streaming raw	ethernet	ethernet	ethernet	wifi	wifi/ethernet18	ethernet18	ethernet	ethernet
Websocket streaming	ethernet	ethernet	ethernet	wifi	wifi/ethernet18	ethernet18	ethernet	ethernet
HTTP daemon (server)	ethernet	ethernet	ethernet	wifi	wifi/ethernet18	ethernet18	ethernet	ethernet
WebDAV to SD card	ethernet	ethernet	ethernet	wifi	wifi/ethernet18	ethernet18	ethernet	no (?)
FTP to SD card	ethernet	ethernet	ethernet	wifi	wifi/ethernet18	ethernet18	ethernet	no (?)
SD Card streaming	yes	yes	yes	yes	yes	yes	no	no
I2C Keypad	yes	yes	yes	yes	yes	yes	no	no
I2C IO Expander	no	no	no	yes	yes	yes	no	no
Digital Aux I/O	3/416	yes	yes	no	0/816	0/816	no	no
MPG stream input	TBC	no	no	no	yes	yes	yes	yes
Manual tool change5	yes	yes	yes	yes	yes	yes	yes	yes
Automatic tool change6	no	no	no	no	no	no	no	no
Laser PPI mode7	yes	yes	yes	no	no	no	no	no
Trinamic support8	TBC9	TBC9	TBC9	TBC9	TBC9	TBC9	TBC9	TBC9
Runs as FreeRTOS task	no	no	no	yes	no	no	option	no
CNC BoosterPack support	yes10	no	no	yes10	yes10	yes10	2	2
WebUI support	yes12	yes12	yes12	yes12	yes12	yes12	yes12	no
Compiler/IDE	Arduino	STMCubeIDE	STMCubeIDE	ESP IDF	VS Code	VS Code	CCS	CCS
Web Builder support19	yes	yes	yes	yes	yes	yes	no	no

With floating point unit FPU:

grblHAL does a lot of floating point math, a FPU will improve performance.

Processor ->	STM32F7xx	STM32F4xx	STM32F3xx	MSP432	TMC123
Board	BTT SKR3 / WeAct MiniSTM32H743	Blackpill / Nucleo-F411RE / Nucleo-F446RE	BlackPill	LaunchPad	LaunchPad
MCU speed MHz	450	84/100/180	72	48	80
Non-volatile storage	Flash1	Flash1	Flash1	Flash1	EEPROM
Number of axes	3	up to 6	up to 6	3	3
Variable spindle	yes	yes	yes	yes	yes
Ramped spindle	no	no	no	no	yes
Inverted spindle PWM	no	no	no	yes	yes
RC Servo/ESC for spindle13	yes	yes	yes	yes	yes
ModBus spindle14	no	no	no	yes15	no
Spindle at speed	yes	yes	no	yes3	no
Spindle sync	yes4	yes4	no	yes4	no
Closed loop spindle RPM	no	no	no	no	no
Native USB streaming	yes	yes	yes	no	no
SD Card streaming	yes	yes	TBC	no	yes
I2C Keypad	no	no	yes	yes	yes
I2C IO Expander	no	no	no	no	no
Digital Aux I/O	no	2/216	no	no	no
MPG stream input	no	no	no	yes	yes
Manual tool change5	yes	yes	yes	yes	yes
Automatic tool change6	no	no	no	planned	no
Laser PPI mode7	yes	yes	no	no	yes
Trinamic support8	TBC9	TBC9	TBC9	TBC9	TBC9
CNC BoosterPack support	no	no	yes10	1	1
Compiler/IDE	STMCubeIDE	STMCubeIDE	STMCubeIDE	CCS	CCS
Web Builder support19	yes	yes	No	no	no

Without floating point unit FPU:

Processor ->	RP 20404	STM32F1xx11	SAM3X8E	SAMD21	LPC1768/1769	PSoC 5	MSP430F5529
Board	Pi Pico	Bluepill	Due	MKRZERO	Re-Arm / Bigtreetech SKR 1.3 / BTT SKR 1.4	CY8CKIT-059	LaunchPad
MCU speed (MHz)	125	72	84	48	100/120	80	25 (16 bit)
Non-volatile storage	Flash1	Flash1	Flash1	Flash1	Flash1	EEPROM	no1
Number of axes	up to 6	up to 6	up to 6	3	up to 5	32	3
Auto-squared/ganged axes17	yes	yes	yes	no	yes	no	no
Variable spindle	yes	yes	yes	yes	yes	yes	yes
Ramped spindle	no	no	no	no	no	no	no
Inverted spindle PWM	yes	yes	no	no	no	no	yes
RC Servo/ESC for spindle13	yes	yes	yes	yes	yes	no	yes
ModBus spindle14	yes	no	no	no	no	no	no
Spindle at speed	no	no	no	no	no	no	no
Spindle sync	no	no	no	no	no	no	no
Closed loop spindle RPM	no	no	no	no	no	no	no
Native USB streaming	yes	yes	yes	yes	yes	no	no
SD Card streaming	yes	yes	no	yes	yes	no	no
I2C Keypad	yes	yes	no	yes	no	yes	no
I2C IO Expander	yes	no	no	yes	no	no	no
Digital Aux I/O	0/816	no	no	no	no	no	no
MPG stream input	yes	no	no	no	no	no	no
Manual tool change5	yes	yes	yes	yes	yes	yes	no
Automatic tool change6	no	no	no	no	no	no	no
Laser PPI mode7	no	no	no	no	no	no	no
Trinamic support8	TBC9	TBC9	TBC9	TBC9	no	no	no
CNC BoosterPack support	yes10	yes10	no	yes10	no	no	1
Compiler/IDE	VS Code	STMCubeIDE	Arduino	Arduino	MCUExpresso	PSOC Creator	CCS
Web Builder support19	yes	yes	yes	no	no	no	no

¹ Plugin for I2C EEPROM or FRAM available. FRAM is faster and can sustain more write cycles than EEPROM. FRAM is reccomended for the Odometer plugin.
² Should be fairly easy to extend.
³ In combination with ramped spindle, signals end of ramp - not programmed speed obtained.
⁴ To be completed TBC, work in good progress.
⁵ Protocol extension, requires compatible GCode sender such as ioSender.
⁶ grblHAL core has functionality and HAL driver entry points are provided, needs verification!
⁷ Driver specific M codes added for control. PPI = Pulses Per Inch.
⁸ Initial version ready for TMC2130 drivers, new CNC BoosterPack design for Texas Instrument LaunchPads ready and initial testing ok.
⁹ Implementation provided for TMC2130, with initial focus on I2C interfaces. Work in good progress - code published.
¹⁰ Via "motherboard" that accommodates CNC BoosterPack and processor board. Prototypes made, includes 8-bit I2C GPIO expander not available/needed for STM32F1xx or IMXRT1062. "motherboards" has option for isolated level-shifted spindle PWM or DC output. BoosterPack has an onboard EEPROM and an I2C level shifter.
¹¹ Requires 128KB of flash STM32F103CB, some STM32F103C8 based Bluepill boards has that. Not recommended due to limited memories, use a STM32F303 or STM32F411 based Blackpill instead for a board with the same form factor as Red- and Bluepills.
¹² Luc's ESP3D-WEBUI. Support both v2 and v3, with auto-detect feature.
¹³ Set $33=50 (PWM frequency), $34=5, $35=5 and $36=10 to generate a "standard" PWM signal: 20ms repetition rate, 1 - 2ms pulse length range.
¹⁴ Supports a number of VFDs. Defaults to 19200 baud, implicit spindle at speed. Not supported for all alternative board map files.
¹⁵ Auto direction detect only.
¹⁶ Dependent on breakout board and plugin configuration.
¹⁷ Dependent on breakout board capability. ABC motors will be added from the first motor available and upward, auto-squared/ganged motors from the last and downward.
¹⁸ Ethernet is via SPI interface to an external WizNet W5100S or W5500 module. Not necessarily supported by all boards.
¹⁹ The Web Builder can be used to create the firmware without installing a toolchain.

Please note that some of the capabilities should be fairly easy to port from one driver to another, but be aware some are dependent on MCU peripheral availability and thus not possible, or hard, to port.

The fastest and most deterministic MCUs seems to be iMRXT1062, STM32H7xx and STM32F7, ESP32 is not bad but it is a bit unstable - maybe due to outstanding bugs in the ESP-IDF and the system architecture - program code is stored off chip in external serial flash.

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Excel tables to markdown done with thisDaveJ web-based utility.

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2024-01-15