Datasheet

17
1745FS–ATARM–18-Apr-06
AT91M55800A Summary
configure up to eight 16-Mbyte banks. In all cases it supports byte, half-word and word aligned
accesses.
For each of these banks, the user can program:
• Number of wait states
• Number of data float times (wait time after the access is finished to prevent any bus
contention in case the device is too long in releasing the bus)
• Data bus width (8-bit or 16-bit)
• With a 16-bit wide data bus, the user can program the EBI to control one 16-bit device
(Byte Access Select Mode) or two 8-bit devices in parallel that emulate a 16-bit memory
(Byte-write Access mode).
The External Bus Interface features also the Early Read Protocol, configurable for all the
devices, that significantly reduces access time requirements on an external device.