2x PSRAM's only show 8mb with test sketch


Well-known member
I'm running the test sketch that Paul has linked here: https://www.pjrc.com/store/psram.html
The sketch shows 8mb but I have 2x PSRAM's on the board.

From what I understand having 2 PSRAM's should just work automatically(?)
I've double checked the soldering as well.

I'm out of ideas to try.

Here is my schematic:

Yes, 2 PSRAM chips definitely do work automatically (as 16MB) when soldered to the bottom side of Teensy 4.1.
That's good to know atleast!
In other words, my schematic is correct since it's copied straight of the 4.1. And the APS6404L-3SQR-ZR works fine as a single (8mb) PSRAM, it should then also work in a pair?

What would you try next?
Some combination of reheating the solder, checking your wiring, and/or soldering 2 to the Teensy 4.1 so you can see if really does work and have a known-good case to compare.
Footprint of these are tiny, will take time to solder them onto a 4.1. But that will ofc be my last resort to verify. And it's leaning towards that.
Atleast now I got confirmation that it should just work. Thanks Paul and good work on the new forum, it's mint!

Solution: 1x PSRAM works fine with 132mhz FlexSPI, but when having 2 of them, only one seems to work.
I dropped the mhz down to 88mhz and that made the test sketch register 16mb. Time to play around and find the fastest speed it'll play with.
Update on that will be posted here.
Just to clear (future?) confusions, m = milli, M = mega, its best to get this right. Also b = bit, B = byte. So MHz, Mb and MB