M5251C3 Evaluation Board Users Guide, Rev. 0
2-2
Freescale Semiconductor
An additional function called the “TRAP 15 handler” allows the user program to utilize various routines
within dBUG. The TRAP #15 handler is discussed in
Section 2.5, “TRAP #15 Functions
”
The operational mode of dBUG is shown in
. After the system initialization, the board waits for
a command-line input from the user terminal. When a proper command is entered, the operation continues
in one of the two basic modes. If the command causes execution of the user program, the dBUG firmware
may or may not be re-entered, at the discretion of the user’s program. For the alternate case, the command
will be executed under control of the dBUG firmware, and after command completion, the system returns
to command entry mode.
During command execution, additional user input may be required depending on the command function.
For commands that accept an optional <width> to modify the memory access size, the valid values are:
•
B 8-bit (byte) access
•
W 16-bit (word) access
•
L 32-bit (long) access
When no <width> option is provided, the default width is .W, 16-bit.
The core ColdFire® register set is maintained by dBUG. These are listed below:
•
A0-A7
•
D0-D7
•
PC
•
SR
All control registers on ColdFire® are not readable by the supervisor-programming model, and thus not
accessible via dBUG. User code may change these registers, but caution must be exercised as changes may
render dBUG inoperable.
A reference to “SP” (stack pointer) actually refers to general purpose address register seven, “A7.”
2.2
Operational Procedure
System power-up and initial operation are described in detail in
Section 1.7, “System Power-up and Initial
2.2.1
System Power-up
1. Be sure the power supply is connected properly prior to power-up.
2. Make sure the terminal is connected to TERMINAL (P4) connector.
3. Turn power on to the board.
shows the dBUG operational mode.
Summary of Contents for freescale M5251C3
Page 1: ...Document Number M5251C3UG Rev 0 05 2006 M5251C3 Evaluation Board Users Guide ...
Page 6: ...M5251C3 Evaluation Board Users Guide Rev 0 vi Freescale Semiconductor ...
Page 18: ...M5251C3 Evaluation Board Users Guide Rev 0 1 12 Freescale Semiconductor ...
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Page 68: ...M5251C3 Evaluation Board Users Guide Rev 0 B 6 Freescale Semiconductor ...
