Rainbow Electronics W90N740 - Manual (Page 5)

W90N740
Publication Release Date: November 26, 2004
- 1 - Revision A4
1. GENERAL DESCRIPTION
The W90N740 micro-controller is 16/32 bit, ARM7TDMI based RISC micro-controller for network as
well as embedded applications. An integrated dual Ethernet MAC, the W90N740, is designed for use in
broadband routers, wireless access points, residential gateways and LAN camera.
The W90N740N is built around The ARM7TDMI CPU core designed by Advanced RISC Machines, Ltd.
And achieves 80MHz under worse conditions. Its small size, fully static design is particularly suitable
for cost-sensitive and power-sensitive applications. It designs as Harvard architecture by offering an 8K-
byte I-cache/SRAM and an 2K-byte D-cache/SRAM with flexible configuration and two way set
associative structure to balance data movement between CPU and external memory. Four stages write
buffer also improves latency for write operations.
The external bus interface (EBI) controller provides single bus architecture, 8/16/32 bit data width to
access external SDRAM, ROM/SRAM, flash memory and I/O devices. It achieves same frequency as
CPU core to minimize latency if internal cache misses. Memory controller supports different kinds of
SDRAM types and configurations to ease system design. The System Manager includes an internal 32-
bit system bus arbiter and a PLL clock controller. Generic I/O bus is easily served as PCMCIA-like
interface for 802.11b wireless LAN connection.
Two 10/100Mb MACs of Ethernet controller is built in to reduce total system cost and increase
performance between WAN and LAN port. Either MII or RMII of MAC is selected for external 10/100
PHY chip to design for varieties of applications. A powerful NAT accelerator (Patent Pending) between
LAN and WAN reduces the software loading of CPU and speeds up performance between LAN and
WAN.
W90N740 integrates root hub of USB 1.1 host controller with one port transceiver and uses
additional port with external transceiver if necessary, which can add valuable functions like flash disk,
printer server, Bluetooth device via USB port. The important peripheral functions include one full wired
high speed UART channel, 2-Channel GDMA, one watch-dog timer, two 24-bit timers with 8-bit pre-
scale, 20 programmable I/O ports, and an advanced interrupt controller.
2. FEATURES
Architecture
• Highly-integrated system for embedded Ethernet applications
• Powerful ARM7TDMI core and fully 16/32-bit RISC architecture
• Big /Little-Endian mode supported
• Cost-effective JTAG-based debug solution
System Manager
• System memory map & on-chip peripherals memory map
• The data bus width of external memory address & data bus connection with external memory
• Bus arbitration supports the Fixed Priority Mode & Rotate Priority Mode
• Power-On setting
• On-Chip PLL module control & Clock select control