External Bus Configuration

The XC167 device provides a highly configurable and flexible BUS system for off-chip memory and peripheral devices.

• On the MCBXC167 board, three devices are connected to this BUS system: Flash, RAM, and the Ethernet Controller.
• These devices connect to the chip select lines CS0 (Flash), CS1 (RAM), and CS2 (Ethernet Controller).
• The ADDRSELx registers select the address window in which the respective Chip-Select signal is active.
• All devices on the MCBXC167 board use an asynchronous de-multiplexed 16-bit BUS. This BUS mode configures in the registers FCONCS0 - FCONCS2.

Bus timings are critical. They depend on the internal clock frequency, the connected memory, and the peripheral devices. For the devices on the MCBXC167 board, the following table lists the fastest possible BUS settings for an internal clock of 40MHz: