FM25V05 - 512Kb SPI FRAM
System Hookup
The SPI interface uses a total of four pins: clock,
data-in, data-out, and chip select. A typical system
configuration uses one or more FM25V05 devices
with a microcontroller that has a dedicated SPI port,
as Figure 3 illustrates. Note that the clock, data-in,
and data-out pins are common among all devices.
The Chip Select and Hold pins must be driven
separately for each FM25V05 device.
For a microcontroller that has no dedicated SPI bus, a
general purpose port may be used. To reduce
hardware resources on the controller, it is possible to
connect the two data pins together and tie off the
Hold pin. Figure 4 shows a configuration that uses
only three pins.
Figure 3. 1Mbit (128KB) System Configuration with SPI port
Figure 4. System Configuration without SPI port
Rev. 2.0
May 2010
Page 4 of 16
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
