Keil MCB251, User Manual

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MCB251 Evaluation Board User’s Guide 17
Both serial ports are configured as a
standard 3-wire interface. The handshaking
signals are connected to loop the PC’s
signals back. Refer to the figure at the right
to determine how the DB9 connector for this
port is wired.
Prototyping Area
A perforated area is provided on the MCB251 for prototyping your own
hardware. All CPU signals necessary to create a 40-pin DIP plug for emulating
an 8051 or 251 in a 40-pin DIP package are connected to this prototyping area.
In addition, the data and address bus signals and the user chip select signal are
connected to this area. The signals provided are driven directly by the CPU.
Exercise caution to avoid overloading these signal lines. Refer to “DIP
Switches” on page 6 for the pin-out of the CPU and bus signals.
NOTE
Since the MCB251 supports both the page mode and non-page mode you should
connect memory-mapped devices directly to the data bus DB0-DB7 and A0-A15.