General Information
Functional Overview
M68HC12A4EVB Evaluation Board — Rev. 1
User’s Manual
MOTOROLA
General Information
21
The MC68HC812A4’s two serial communications interface (SCI) ports are
associated with separate RS-232C interfaces. D-Bug12 uses one of the SCIs for
communications with the user terminal (jumper-selectable, SCI0 by default).
The second SCI port is available for user applications. For information on the
ports and their connectors, refer to
2.5 EVB to Terminal Connection
and
4.5
Terminal Interface
.
If the MCU’s single-wire background debug mode (BDM) interface serves as
the user interface, both of the SCI ports become available for user applications.
This mode requires a background debug development tool, such as Motorola’s
serial debug interface (SDI), and a host computer with the appropriate interface
software. For more information, refer to
Appendix F. SDI Configuration
and
to the Serial Debug Interface User’s Manual, Motorola document order number
SDIUM/D.
NOTE:
D-Bug12 does not use the BDM interface.
Two methods may be used to generate EVB user code:
•
For small programs or subroutines, D-Bug12’s single-line
assembler/disassembler may be used to place object code directly into
the EVB’s memory.
•
For larger programs, the Motorola MCUez
assembler may be used on
a host computer to generate S-record object files, which then can be
loaded into the EVB’s memory using D-Bug12’s LOAD command.
The EVB features a prototype area, which allows custom interfacing with the
MCU’s I/O and bus lines. These connections are broken out via headers J8 and
J9, which are immediately adjacent to the prototype area as shown in
Figure 1-1
.
An on-board push-button switch, S1, provides for resetting the EVB hardware
and restarting D-Bug12. Another on-board switch, S2, allows aborting the
execution of a user program, useful in regaining control of a runaway program.
Both of these switch functions are available for customized use in the prototype
area.
The EVB can begin operation in either of two jumper-selectable (W20) modes
at reset. In normal mode, D-Bug12 immediately issues its command prompt on
the terminal display and waits for a user entry. In the alternate mode, execution
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Freescale Semiconductor, Inc.
For More Information On This Product,
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