Summary

Thats about all there is to a flash interface. The implementation discussed here has a front end that you can reuse across virtually any bus-based flash device configuration. The API and commands provide an interface between the user and flash device that requires the user to realize that the address space dedicated to flash memory is written and erased through an API. As long as the API is followed, the writes and erases will succeed, regardless of the underlying device.

At the application level, the flash interface discussed in this chapter is a convenience. At the driver level, someone still must write the protocol necessary to interface to the device (similar to what we just went through with the 29F040 device). Recall that the 29F040 is one of a family of devices that are similar in their architecture and interface. This family implements a device ID feature, allowing firmware to self-configure for whatever device is actually soldered on the board. Because the device is self-identifying, you can build target hardware with one of several different devices of the same family without making any changes to the firmware. This solution is adequate for simple environments in which the device is soldered on the target board, and for which, at most, one or two different device types are supported