mc68336 Freescale Semiconductor, Inc, mc68336 Datasheet - Page 28

• Manufacturer Part Number: mc68336
• Description: An Introduction To The Mc68331 And Mc68332
• Manufacturer: Freescale Semiconductor, Inc

The debugger should now work reliably. That is, programs can be downloaded into the RAM and executed.
Alternatively, write the reset vector to memory location $000000. The reset vector is discussed in detail in
4.1.3.1 Initializing the Reset Vector
3.2 Communicating with Freescale Boards
Third party vendors sell many types of development tools to help establish communication with the MCU.
These development tools are described in the Freescale Microcontroller Development Tools Directory
(MCUDEVTLDIR/D). However, this tutorial focuses only on Freescale evaluation boards.
3.2.1 The M68EVK331 and M68EVK332
The M68EVK332 (A or G) and the M68EVK331 are an evaluation kit that consists of two components: a
platform board (PFB) and a business card computer (BCC). The PFB has logic analyzer connectors and
sockets for external memory. The BCC is a plug-in daughter board that holds the MCU, RAM, and a boot
EPROM. On older versions of the BCC, the EPROM is soldered to the board and cannot be easily repro-
grammed. However, on newer versions of the BCC, the EPROM is socketed and can easily be removed
and reprogrammed.
There are two ways to communicate with the EVK: serial communication using the ROM monitor in the
EPROM and background debug mode (BDM) using a debugger. Both are valid ways of debugging code;
however, the user interface for BDM is much more user-friendly.
3.2.1.1 Communication Using the ROM Monitor
The EPROM contains a monitor program called CPU32Bug (332Bug in older versions of the BCC).
CPU32Bug consists of both initialization code and a user interface. The initialization code sets the system
clock to 16.778 MHz, disables the software watchdog, and configures chip-selects zero, one, and two,
which are necessary to talk to the RAM. The user interface uses the serial communication interface (SCI)
to give a prompt on a computer screen and allow the user to modify memory, load, trace, and run programs.
The CPU32Bug Debug Monitor User’s Manual (M68CPU32BUG/D) explains more about the capabilities of
CPU32Bug.
Terminal emulation programs for the Macintosh, such as MacTerminal or Red Ryder, and communications
software for the IBM-PC, such as Kermit or PROCOMM, are acceptable for use with the EVK. The
M68332EVK Evaluation Kit User’s Manual (M68332EVK/AD1) explains the necessary steps to follow for
each type of software. This section will only explain how to use PROCOMM with the EVK.
First, assemble a cable as shown in Figure 18. The 25-pin connector goes to the serial port on the PC, and
the 9-pin connector goes to P9 (terminal from BCC) on the EVK. Connect the cable from the appropriate 9-
pin serial port on the EVK to the serial port on the PC. Then, execute the communications program. As an
example, for PROCOMM PLUS, set up PROCOMM to match the EVK baud rate and protocol as follows:
Set up ASCII transfer parameters as follows:
Now, apply power to the EVK and press the keyboard carriage return (<CR>) key to display the EVK monitor
prompt. If necessary, press the BCC RESET button on the EVK.
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9600 baud, no parity, eight bits, one stop bit, full duplex
Echo Local — No
Expand Blank Lines — Yes
Pace Character — 0
Character pacing — 15 (milliseconds)
Line pacing — 10
CR Translation — None
LF Translation — None
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
M68331/332TUT/D
MC68331/332