Teensy 4.1 Pins 42 - 54

[dwilliams]

I am working on a project with Teensy 4.1 that requires 53 I/O pins. After working on the project, I have come to realize that the SD and QSPI pins are not easily accessible in a PCB. Has anyone connected these pins to PCB?

I don't think I will need the extra memory or an SD card, so their primary uses are not important to me. I just want to use them for digital I/O. Thanks.

 

[MichaelMeissner]

I am working on a project with Teensy 4.1 that requires 53 I/O pins. After working on the project, I have come to realize that the SD and QSPI pins are not easily accessible in a PCB. Has anyone connected these pins to PCB?

I don't think I will need the extra memory or an SD card, so their primary uses are not important to me. I just want to use them for digital I/O. Thanks.

For accessing the micro SD card pins (42-47), you can use something like the microSd card sniffer from Sparkfun (https://www.sparkfun.com/products/9419). Here is the design as a PCB you can order from OSH park: (https://oshpark.com/shared_projects/bxBIb105).

In terms of the underneath pins (48-52), you may need to go diving into the source to see what the Teensy initialzation routines do to identify if flash and PSram memories may be soldered to the board.

 

[dwilliams]

For accessing the micro SD card pins (42-47), you can use something like the microSd card sniffer from Sparkfun (https://www.sparkfun.com/products/9419). Here is the design as a PCB you can order from OSH park: (https://oshpark.com/shared_projects/bxBIb105).

Thanks, do I need to have a microSD card plugged in for that to work?

 

[defragster]

Thanks, do I need to have a microSD card plugged in for that to work?

No, using those pins for GPIO would only work when no SD card access was required, and the SD card not present. Both 'software' and the physical interconnect would preclude SD card usage.

The indicated sniffer type 'card' PCB is inserted into the socket like an SD card and brings the pin signals out IIRC to solderable pin connection points.

The original (previously available) SD socket adapter relies on pad contacts on the leading edge of the SD adapter - they are close pitch near the socket opening and not likely easily or reliably solderable. Supply chain availability has required a change in the T_4.1 SD card socket used that has moved those front edge pads inward under the upper cover of the SD socket so even those visible pad connects will be changing going forward.