Teensy 3.2 custom board advices

[Manu]

Hello,

I'm currently review a project I have that involve a Teensy 3.2 custom board. The circuitry is achieved but I had some clues. Here is the teensy schematic part of the project :



This project involve CAN, SPI and USB for configuration. It have 4 SPI devices (CS-1 to CS_4).

My mains doubts are about VBAT, VDDA and VSSA. Does they need to be connected when not using a backup battery and analogue inputs ?

Any advice is welcome, and if anyone have 5 minutes to spend on the schematic I thank her/him for telling me if any problem is present (or not).

Thank,
Manu

 

[Frank B]

Hello,

I'm currently review a project I have that involve a Teensy 3.2 custom board. The circuitry is achieved but I had some clues. Here is the teensy schematic part of the project :

View attachment 14844

This project involve CAN, SPI and USB for configuration. It have 4 SPI devices (CS-1 to CS_4).

My mains doubts are about VBAT, VDDA and VSSA. Does they need to be connected when not using a backup battery and analogue inputs ?

Any advice is welcome, and if anyone have 5 minutes to spend on the schematic I thank her/him for telling me if any problem is present (or not).

Thank,
Manu

No Bootloader?
VBAT needs a connection to 3.3Volt. VDDA, VSSA..don't know. I think, not.

 

[crees]

I successfully made a custom teensy 3.2 based board. Couple observations. One is missing ferrites And circuit connecting them. Vbat must not be left floating. I recommend following 3.2 schematic as close as possible. Crystal is a very important on layout and traces. Usb also should follow differential rules. Like the previous post I wonder why your omitting the boot loader chip (are you programming the MK20 before installing?). Not that it’s required after you have the chip programmed but you may have challenges if you plan to update it later.

 

[Manu]

Thank to every body who reply
I attached VBAT to VCC.
Bootloader is part of another board that is only used when programming MK20 is needed. This project don't expect to be field upgradable.

Thank also for differential rules for usb, I forget about it !

I don't understand ferrites concerns. Can you develop your thought ?
Thank,
Manu

 

[crees]

Thank to every body who reply
I attached VBAT to VCC.
Bootloader is part of another board that is only used when programming MK20 is needed. This project don't expect to be field upgradable.

Thank also for differential rules for usb, I forget about it !

I don't understand ferrites concerns. Can you develop your thought ?
Thank,
Manu

You may not need them unless your using the ADC functionality etc. others here may have expertise ommiting them.