Some doubts about the myFP2ESP-TMC22XX PCB

[Julio Hornos]

I am mounting the myFP2ESP-TMC22XX PCB and I have some doubts
I can see the J16 (PBOEN) and J17 (PBIEN), what is the main function for this connectors?
Another doubt is about the IC3, in the schema I see IC3 7805 but in the circuit rev3 I can see IC3 7808, what of these is it better to use?
It is necessary to use a heat sink for the IC3?, because it is no space enough in the PCB and in this case I will put outside PCB.

Thanks,
Regards,

[brownrb]

I can see the J16 (PBOEN) and J17 (PBIEN), what is the main function for this connectors?

Apologies,
From PDF pg 33, Using Push buttons
PCB revisions (ESP32-DRV8825-Rev6 and ESP32-ULN2003-Rev4) have two special jumpers J16-PBOEN and J17-PBIEN which must be closed (using a motherboard shunt jumper) to enable the push button switches.

AND
pg 37, Using a Joystick instead of push buttons
Resistors R1 (10K) and R2 (10K) should NOT be fitted if the joystick is used.

That applies to most boards including tmc boards.

Another doubt is about the IC3, in the schema I see IC3 7805 but in the circuit rev3 I can see IC3 7808, what of these is it better to use?

Difficult question - it depends on esp32 board and manufacturer as to how they derive 5v from the USB and how this is fed to VIN on the esp32 chip.

In this case, there are no other devices (temp probe) that require 5v, and the 30pin chip does not generate 5v for use by any device, so it is safe to power from 8V using an LM7808

In other projects, you will find an LM7805 is used. The reason for this is that the 5V is needed for other sensors on the board because some sensors will not work at 3v3.

In the focuser I prefer to use LM7808 to ensure that the board uses this instead of 5V from USB.

But you can use either for this project.

Do you need to use a heatsink?

There is the esp32 chip running wifi, the temperature probe, the display, the ir remote, the in/out led indicators that use power derived from the voltage regulator.

If you are not using all of them, then no heatsink should not be required.
The esp32 - 80mA average, 500mA max
The probe is minimal around 1.5mA max
The OLED is around 15mA max
or
The LCD is any where from 1mA to max 150mA depending on manufacturer and backlight setting
The LED's around max 15mA (only one is on at a time)
The Buzzer around max 32mA

Then all the various components and the chip itself.
From recall, I think it was about 200mA when doing things, but when not moving (idle) was around 120-150mA (again from memory).

Heat (watts) = Volts * Current
= 3.3 * 0.150 = 0.5 watts (max)

But when doing stuff like moving
= 3.3 * 0.600 = 2 watts

I thought there was enough space on the PCB to fit the heat sink. The heat sinks I normally use are 201510 which have a depth of 10mm, which way round are you placing the heat sinks?

[Julio Hornos]

Thanks for your reply,

I take note of your recommendations.
In my case I am not going to use joystick, I am going to use push buttons, so I am going to close the J16 and J17 with a shunt jumper. Ok, I have found this in myFP2ESP-230.pdf file, sorry.
For the heatsink, I am going to use all that you see, so in need it. I have found the once you told me, but I was prepared a modification of one I bought to fit in the motherboard (attach a picture)

Regards and thanks for all,