Device Interface Functional Overview
Device Connection
Copyright © 2002 Marvell
CONFIDENTIAL
Doc. No. MV-S300165-00, Rev. A
May 21, 2002, Preliminary
Document Classification: Proprietary Information
Page 51
Section 6. Device Interface Functional Overview
The device controller supports up to five banks of devices. Each bank’s supported memory space can be sepa-
rately programmed in 1 MB granularity up to 512 MB of address space, resulting in a total device space of 2.5 GB.
For pinout information of the device interface, see the GT-64260A datasheet’s "Pin Information" section.
6.1
Device Connection
The device AD bus is a 32-bit multiplexed address/data bus. During the address phase, the device controller puts
an address on the AD bus with a corresponding chip select asserted and DevRW indicated. It de-asserts Address
Latch Enable (ALE) to latch the address, the chip select, and read/write pins by an external latch.
To connect more than five devices, use an external logic. The external logic can use the CS*[3:0], BootCS*, and
the address pins to generate additional Device_CS* pins. For example, use CS*0 to select two devices. In this
case, the address can be used to determine which device is selected:
•
Device0_CS* = Address[30] ‘OR’ (CSTiming* ‘OR’ CS*0)
•
Device1_CS* = ‘NOT’(Address[30]) ‘OR’ (CSTiming* ‘OR’ CS*0)
shows an example of how three devices are connected through the GT-64260A device interface connec-
tion.
Note
Since CSTiming* is tri-stated at reset assertion and CS pins qualification may be incorrect, connect a pull-
up resistor on the CSTiming* pin.