General Description - Motorola M68HC11EVB User Manual

GENERAL INFORMATION

1.4 GENERAL DESCRIPTION

The MC68HC11 MCU device is an advanced single-chip MCU with on-chip memory and
peripheral functions. Refer to the MC68HC11 MCU data sheet for additional device information.
To demonstrate the capabilities of this MCU, the EVB functions with a debug monitor program
called BUFFALO (Bit User Fast Friendly Aid to Logical Operations). This monitor program is
contained within an on-board EPROM (external to the MCU).
The EVB provides a low cost tool for debugging and evaluation of MC68HC11 MCU-based
target system equipment (Figure 1-1 is a block diagram of the EVB). The EVB is not intended to
be a replacement for a much more powerful and flexible tool, such as the Motorola
M68HC11EVM Evaluation Module. The EVB operates in either the debugging or evaluation
(emulation) mode of operation.
The first mode of operation lets you debug your code using the BUFFALO monitor program.
User code is assembled on the EVB or on a host computer and then downloaded to the EVB
RAM via Motorola S-records. The second mode of operation lets you evaluate (emulate) user
code in a target system environment utilizing the memory of the MC68HC11 MCU. The EVB
emulates the single-chip mode of operation, even though the EVB operates in the expanded
multiplexed mode of operation at all times.
Overall evaluation/debugging control of the EVB is provided by the BUFFALO monitor program
via terminal interaction. The target system interface is provided by the MCU and PRU devices.
RS-232C terminal/host I/O port interface circuitry provides communication and data transfer
operations between the EVB and external terminal/host computer devices.
Independent baud rate selection capabilities are provided for the terminal and host I/O ports.
Hardware selectable (300-9600) baud rates are provided for the ACIA-based terminal port. A
non-selectable (fixed) 9600 baud rate is provided for the host port via the MCU Serial
Communications Interface (SCI).
The EVB requires a user-supplied +5, +12, and -12 Vdc power supply and an RS-232C
compatible terminal for operation. An RS-232C compatible host computer is used with the EVB
to download Motorola S-records via the BUFFALO monitor commands.
The Motorola S-record format was devised for the purpose of encoding programs or data files in
a printable format for transportation between computer systems. The transportation process can
therefore be monitored and the S-records can be easily edited. Refer to Appendix A for additional
S-record information.
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