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GT-96100A Advanced Communication Controller
Revision 1.0
21
1.2
CPU Interface
The GT-96100A’s SysAD bus allows the CPU and other local bus masters to access the PCI and memory/device
buses.
The SysAD bus protocol supports byte, sub-word, 32-bit word, and 64-bit word operations with burst lengths of
up to eight words (sub-word, two word, and four word burst length are also supported). With a maximum fre-
quency of 100MHz, the CPU can transfer in excess of 800 Mbytes/sec.
The GT-96100A allows up to four GT-96100A devices, or GT-64120 system controllers, to share the same CPU
interface. This significantly increases the address space, number of communication channels, and flexibility of
system design.1
The GT-96100A supports CPU address remapping to resources and can operate in little or big endian mode.
1.3
SDRAM and Device Interface
The GT-96100A integrates a SDRAM controller with a 64-bit interface.
The SDRAM controller supports 16, 64, 128, 256 and 512Mbit SDRAMs. It is 3.3V and 5V tolerant, operates at
frequencies of up to 100MHz, and can address up to 4GBytes. Up to four SDRAM banks can be connected to the
controller and it supports 2 bank interleaving for 16 Mbit SDRAMs and 2 or 4 bank interleaving for 64/128/256/
512 Mbit SDRAMs.
The SDRAM controller also supports a UMA feature that enables external masters to arbitrate for direct access
to SDRAM. This feature enhances system performance and gives flexibility when designing shared memory sys-
tems.
The GT-96100A device controller supports different types of memory and I/O devices. It has the control signals
and timing programmability to support devices such as Flash, EPROMs, FIFOs, and I/O controllers. Device
widths from 8-bits to 64-bits are also supported.
ECC generation and checking is supported both internally and externally and is optional for each bank of
SDRAM.
1.4
PCI Interface
The GT-96100A interfaces directly to the PCI bus. The PCI interface can be configured to function as either:
Two 32-bit PCI devices (PCI_0 and PCI_1)
A single 64-bit PCI device (PCI_0) operating at a maximum frequency of 66MHz.
Each of the GT-96100A’s PCI interface can either be a master initiating PCI bus transaction or a target respond-
ing to a PCI bus operation.
The GT-96100A incorporates 192-bytes of posted write and read prefetch buffers per PCI device for efficient
data transfer between the CPU bus/DMA to PCI and PCI to main memory.
1. The increased loading will only have a small effect on the system’s maximum operating frequency.