I'm a software developer and trodding in murky waters here so please do forgive my lack of knowledge. I've been developing a sensor with the nRF9160DK and some accelerometers. I need to continuously write data to a memory as the RAM is not enough to hold an entire event.
I've tried a NOR-flash, it was not fast enough, I need to write at least 32kB/s. I tried an sd-card. It was fast enough but allocating new pages took a bit too long and the power drawn was way too high. I'm now thinking of a NAND or FRAM external memory and writing via QSPI. The memory size needs to be at least 8MB which might make FRAM difficult.
Here is where I'd like help. What would you recommend? What draws the least but still fulfills the speed demands? If there is a specific product you have in mind, I'd greatly appreciate it. Or maybe an alternativ, I found this that might be interesting: https://www.electrokit.com/en/product/sparkfun-openlog-2/ as it draws 2mA in idle mode though I doubt that is with the sd-cards draw included. I'm open to any recommendation to solve this! It's the last bump in a very long road I have been traveling.
I should mention I've also tried shutting down the sd-card and starting it first at en event is triggered but the mounting time is too slow(148 ms) and critical data is lost. I could save 148 ms of data in RAM but I don't think the mounting operation can be paused or multithreaded in the required way.
Thank you beforehand and please, ask if I didn't include information I did not know to be vital.