Keil MCB167-NET, User Manual

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MCB167-NET Board User’s Guide 15
Ethernet Interface
The Ethernet controller CS8900A (IC7) is the interface to the Ethernet
connector. The MCB167-NET provides a standard 10Base-T (10MBit) interface
that allows direct connection to most Ethernet networks. The chip select signal
CS2/ from the C167 CPU is used to access the Ethernet controller as memory
mapped device.
Decode Logic
All memory address decode logic and signal conversions required for the
CS8900A Ethernet controller are performed by the 20V8 PAL (IC15). Refer to “
PAL Equations” on page 17 for a complete listing of the PAL equations used.
Status LEDs
The MCB167-NET has a power LED labeled PWR which indicates the power to
the board is on. Eight LEDs are connected to the Port 2 outputs for status
display in user programs. The LEDs labeled LAN and LINK show the current
status of the Ethernet interface.
Push Buttons
The MCB167-NET provides two push buttons. The first push button, labeled
RESET, is connected to the reset input of the CPU. The second button, labeled
NMI, is connected to the NMI (non-mask able interrupt) of the CPU. You may
generate an NMI signal to stop program execution when you are using the
Monitor-166 for program debugging.
Serial Port
The MCB161-NET supports the ASC0 serial UART and uses a MAX232 (IC10)
to convert the logic signals to RS-232 voltage levels. The ASC0 UART is used
in bootstrap mode to download the Monitor-166 program. This Monitor
program allows program test using the µVision2 debugger.
Two drivers of the MAX232 (IC10) are pre-wired to use the simulated serial
mode of the Monitor-166. In this mode two standard I/O pins of the 167 device
are used to establish communication between the µVision2 debugger and the