Many reasons exist to choose a discrete flash chip over an SD subsystem, and vice versa, and you'll need to consider these tradeoffs for your design. Whenever I'm building an Atmel ATMega or Arduino project and I need to record data, I almost always reach for a single SPI WinBond W25Q80BV 1MB flash chip rather than an SD flash subsystem. This is also a follow-on to my other two data-logging Instructables (an anemometer and a 3-axis wrist accelerometer) that explains how to download the data from the logger flash memory using age-old TTY command line applications found in Linux.
This Instructable will show you how to add 1MB of discrete external flash memory to your microcontroller project with what I believe to be the least amount of effort possible. Designing with discrete flash is 1/10th the cost, uses a much smaller form factor, and requires significantly less specialized hardware than using SD flash cards.
