I am new to electronics, but always wanted to build my own devices and decided to start with simple usb flash drive as a first project. I found some reference designs by cypress and it confused me a bit.
https://www.cypress.com/documentation/reference-designs/cy4665-cypress-upek-reference-design-usb-flash-drives-ufd here is the link to reference design.
So the problem is that in this reference design some active low pins are not pulled up at all, so they are basically left floating. For example "Read Enable" (RE) pin and "Write Enable" pins are left floating.
In my project i am using micron NAND flash https://datasheet.octopart.com/MT29F2G16ABAEAWP%3AE-Micron-datasheet-11549997.pdf (the datasheet) and cant find information regarding which pins are in what mode. maybe they are internally pulled up ? maybe pulled down. i am having a trouble finding it.
Maybe somebody can point me to another reference design, or explain why this pins are left floating.