This PSRAM chip can add 8 Megabytes of RAM for use on Teensy 4.1.
The following PSRAM chips have been tested with Teensy 4.1. Your order will be filled with one of these chips.
One PSRAM Chip for 8 MB Memory
The PSRAM chip is meant to be soldered to the smaller pads on the bottom side of Teensy 4.1, underneath the SD card socket, between pins 31-32 and 33-34. Do not use the larger pads. A single PSRAM chip must be solded to the smaller pads to be detected.
Two PSRAM Chips for 16 MB Memory
If 8 MB isn't enough, you can solder 2 PSRAM chips for a total of 16 MB.
One PSRAM Chip with Flash Memory
To use flash memory for non-volatile storage together with PSRAM for large buffers or variables, add the PSRAM chip to the smaller pads and the flash memory to the larger pads.
Memory Test Program
After soldering the PSRAM to your Teensy 4.1, run the memory test program (see link below under 'Documents') to verify the PSRAM memory really is working properly.
Using PSRAM Memory
To use PSRAM memory in Arduino, add EXTMEM to large arrays or other variables you wish to be allocated in the PSRAM. These variables are not initialized and will contain random data when your program starts, so don't forget to set them to zero or fill them with the data you need before use.