Also note the teensy 3.5/6 is around 40$ vs the 2$ for the esp32by aenertia - RAMPS Electronics
tl;dr 6 Analog - 44 useable total (although you can coax another 6 from it if you are brave) Teensy 3.6 has 21 - But you can use any of the 44 pins as PWM - and they can all be software defined on the ESP32 - likewise it has 2 full HW SPI - the teensy only has 1, The ESP also has a secondary ULP core which could be useful potentially as well as HW Crypto lacking on the teensy.by aenertia - RAMPS Electronics
While I'm a fan of the teensy (I have used them in Mech Keyboards for a while) - I am not sure they offer better value over the esp32 - which is now sub 2$ a module and has more punch and features - inbuilt wifi and bt, more ram etc.by aenertia - RAMPS Electronics
T'was a typo - wrt Extruders; I'm just pointing out there are several use cases where multiply more extruders and/or Heads are the norm ; i.e CNC+Lazer+Ext ruder also is a relatively common setup. I am fully aware it's not a shield. But out of the boards on my desk right now 3 are Arduino Nano style pinouts (esp8266 / esp32 lolins) 4 are Arduino Uno (1 espduino and 3 d1 r32 esp32 in uno formfby aenertia - RAMPS Electronics
Is Due event a consideration (it's not even produced anymore) I think to sum it up generally these design goals are somewhat useful 3.3v safe board design. Ability to interface $userschoice of MCU - assume no specific pinout SPI controlled Motor controllers are likely going to be the norm Plug-gable fuses Assume interfacing with a General Purpose offboard for interface (Pi etc) Support for mby aenertia - RAMPS Electronics
wrt MCU Choice - I have several ESP32's lying in front of me right now; however I am eyeing up the STM32F7 dev boards - in particular there is a Nucleo that looks like it will do the job and is reasonably priced at 60$ - this one Also considering the teensy 3.5 board (as it's 5v tolerant which the 3.6 isn't). In all likelyhood my ideal board would have easy interfacing with an H3/5 Pi clonby aenertia - RAMPS Electronics
It's a decided hacked up STM32F4 - Pictures of the board here : I managed to get them to open source there hacked up marlin 1.0.1*mumble* version - on github. Froked mooz3d repo However they went and used some proprietary build chain that is windows only ; so far I haven't even been able to compile off there source drop - but at least in theory the pinouts etc can be divined from the sourcby aenertia - RAMPS Electronics
Couple of comments; as I am looking to replace the stm7f proprietary board in my MOOZ which is proprietary and doubtful due to various SPI backed hacks I can reverse engineer into something usable with Mainline Marlin 2.0 at this point. So some considerations; * ESP32 / $Whatever MCU boards should be well supported - I am over the arduino pinout configuration in general and think that the RAMPSby aenertia - RAMPS Electronics