Hardware Details
The router is based around a Winbond W90N740 ARM-based microcontroller, which boots from 1 MB of flash, and runs from the 4 MB of SDRAM. The 5 network ports are connected to the IP175A ethernet switch IC. The 4 ports labeled on the back of the case with numbers 1 through 4 (the "LAN" ports) are connected to the ethernet switch fabric, along with a connection to the W90N740 ethernet MAC port. The other ethernet port (the one labeled "WAN") is connected to a PHY inside the IP175A that connects to the other MAC port on the CPU. See the block diagram below (for a better view, grab the PDF):
Key to Router PCB
- 1. Winbond W90N740CD ARM-based Microcontroller.
- 2. 1 M * 16-bit SDRAM (2 megabytes) - another 2 megabytes on the bottom of the board. TMtech T431616A.
- 3. 512 K * 16-bit (1 megabyte) flash memory. AM29LV800BB.
- 4. IC Plus Corp IP175A 5-port switch IC (under heat-sink). Configured as a 4-port switch connected to one CPU MAC port, and a one-port PHY attached to the other MAC port.
- 5. Ethernet magnetics/transformers.
- 6. CPU oscillator crystal (15 MHz).
- 7. 3.3V power supply.
- 8. 5V power supply.
- 9. 2.5V power supply (for IP175A).
- 10. IP175A oscillator crystal (25 MHz).
- 11. Serial port circuit (unpopulated).
- 12. Ethernet ports.
- 13. USB 1.1 host port.
- 14. Reset Switch (actually connected to a CPU interrupt, see HW Mods: Step Four).
- 15. JTAG Connector (unpopulated).
On the back of the board, is the 1.8V power supply for the CPU, the other 2 megabyte SDRAM chip, and a schmidt-trigger IC used in the power-on reset circuitry.