Motorola 68HC12B32 User manual

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xiom
anufacturing
CME-12B/BC
Development Board for Motorola
68HC12B32 and 68HC12BC32 Microcontrollers

2
CONTENTSCONTENTS
GETTING STARTED............................................................................................3
Installing the Software.....................................................................3
Board Startup..................................................................................3
Support Software ............................................................................4
Software Development....................................................................4
TUTORIAL............................................................................................................5
Creating source code......................................................................5
Assembling source code.................................................................6
Running your application ................................................................7
Programming Flash EEPROM.........................................................8
MEMORY MAP.....................................................................................................9
CONFIG SWITCH...............................................................................................10
MEM-SEL JUMPERS .........................................................................................10
PORTS AND CONNECTORS ............................................................................11
LCD_PORT...................................................................................11
KEYPAD........................................................................................11
MCU_PORT..................................................................................12
CAN_PORT...................................................................................12
COM1 SERIAL PORT...................................................................13
J2 ..................................................................................................13
BUS_PORT...................................................................................13
BDM-IN .........................................................................................14
EVU Compatibility Jumpers...........................................................14
TROUBLESHOOTING .......................................................................................15
Code Execution ...................................................................... 16
TABLES..............................................................................................................17
TABLE 1. LCD Command Codes.................................................17
TABLE 2. LCD Character Codes..................................................17
TABLE 3. D-Bug12 Monitor Commands.......................................18

3
GETTING STARTED
The Axiom CME-12B/BC single board computer is a fully assembled, fully functional
development system for the Motorola 68HC12B32 and BC32 microcontrollers, complete with
wall plug power supply and serial cable. Support software for this development board is
provided for Windows 95 and NT operating systems and DOS.
Follow the steps in this section to get started quickly and verify everything is working correctly.
Installing the Software
1. Insert the Axiom 68HC12 support disk in your PC. If the setup program does not start, run
the file called "SETUP.EXE" on the disk.
2. Follow the instructions on screen to install the support software onto your PC.
3. The flash programming utilities require you to specify the board you are using. You
should select either “CME-12B32” or "CME-12B/BC" for this board.
Board Startup
Follow these steps to connect and power on the board. This assumes you're using the
provided AXIDE or AX12 terminal program (installed in the previous section) or a similar
communications terminal program on your PC. If you're using a different terminal program
than the one provided, set it's parameters to 9600 baud, N,8,1.
1. Make certain the CONFIG SWITCH is set as follows:
1234 567 8
ON ON ON ON OFF ON OFF OFF
2. Connect one end of the supplied 9-pin serial cable to a free COM port on your PC.
Connect the other end of the cable to the COM1 port on the CME-12B/BC board.
3. Apply power to the board by plugging in the power adapter that came with the system.
4. If everything is working properly, you should see a message to “PRESS KEY TO START
MONITOR…” in your terminal window. Press the ENTER key and you should see:
D-Bug12 v2.0.2
Copyright 1996 - 1997 Motorola Semiconductor
For Commands type "Help"
> _
5. Your board is now ready to use! If you do not see this message prompt, or if the text is
garbage, see the TROUBLESHOOTING section at the end of this manual.

4
Support Software
There are many useful programs and documents on the included HC12 support disk that can
make developing projects on the CME-12B/BC easier. You should browse the disk and copy
anything you want to your hard drive. See the README.TXT file for a description of what is
included.
The flash programming utilities communicate with the board via its COM1 port and the
supplied cable. These programs also include a simple Terminal for interfacing with other
programs running on the CME-12B/BC, such as the D-Bug12 and information from your own
programs that send output to the serial port.
Also on the disk is a free assembler, example source code, and other tools to get you started.
Software Development
Software development on the CME12B32 can be performed using either the DBUG12 monitor
utility installed in EPROM (sockets U6/U7), the DBUG12 monitor programmed into the internal
Flash EPROM or a Background Debug Module (BDM) connected to the BDM-IN connector.
Any of these tools can be used to assist in creating and debugging your program stored in
either internal RAM ($800-$C00) or external RAM (U4/U5 see Memory Map).
After satisfactory operation running under a debugger, your program can be written to the
Internal Flash Memory by relocating its start address to $8000 and programming it using
either the included programming utilities or a BDM. Your program will then run automatically
whenever the board is powered on or RESET is applied.
Option jumpers and switches on the board allow for easy transition from one memory type to
another and restoring an operating monitor.

5
TUTORIAL
This section was written to help you get started developing software with the CME-12B/BC
board. Be sure to read the rest of this manual as well as the documentation on the disk if you
need further information.
The following sections take you through the complete development cycle of a simple "hello
world" program, which sends the string "Hello World" to the serial port.
Creating source code
You can write source code for the CME-12B/BC board using any language that compiles to
Motorola 68HC12 instructions. Included on the software disk is a free Assembler and also a
freeware C compiler and Basic compiler.
You can write your source code using any ASCII text editor. You can use the free EDIT or
NOTEPAD programs that come with your computer. A better code editor can be downloaded
at: http://www.winedit.com. Once your source code is written and saved to a file, you can
assemble or compile it to a Motorola S-Record (hex) format. This type of output file usually
has a .MOT, .HEX or .S19 file extension and is in a format that can be read by the
programming utilities to be programmed into the CME-12B/BC board.
It's important to understand your development board's use of Memory and Addressing when
writing source code so you can locate your code at valid addresses. For example, when in
debug mode, you should put your program CODE in External RAM. In assembly language,
you do this with ORG statements in your source code. Any lines following an ORG statement
will begin at that ORG location, which is the first number following the word ORG, for example:
ORG $2000.
You must start your DATA (or variables) in a RAM location unused by your program, for
example: ORG $1000. When finished debugging, you must change these ORG statements so
that your program is moved to a valid EEPROM area - somewhere after hex 8000. Do this by
putting an ORG $8000 in front of your Program CODE. Data may remain where it is or be
moved down to internal RAM starting at ORG $800. You must also program the STACK
register somewhere at the top of your available RAM, for example hex BFF. Do this with this
instruction as the first instruction in your program code: LDS #$0BFF.
A look at the example programs on the disk can make all of this clearer. If you're using a
compiler instead of an assembler, consult the compiler documentation for methods used to
locate your code and data.
Source code created to run under the D-bug12 monitor environment will be slightly different
than code written for stand-alone operation. The monitor contains interrupt and RESET
vectors that your code must provide when it's no longer running under the monitor. See the
Programming Flash EEPROM section for more information on this.

6
Assembling source code
An example program called “HELLO.ASM” is provided under the \EXAMPLE directory.
You can assemble your source code using command line tools under a DOS prompt by typing:
AS12 HELLO.ASM –LHELLO
Most compilers and assemblers allow many command line options so using a MAKE utility or
batch file is recommended if you use this method. Run AS12 without any arguments to see all
the options, or see the AS12.TXT file on the disk.
The programming utilities provided with this board also contain a simple interface to the free
assembler. Use it by selecting "Build" or “Assembler” from the menu. This will prompt you for
the file to be assembled.
DO NOT use long path names (> 8 characters). The free assembler is an old DOS tool that
does not recognize them.
If there are no errors in your source code, 2 output files will be created:
HELLO.S19 a Motorola S-Record file that can be programmed into memory
HELLO.LST a common listing file which shows the relationship between source
and output
The listing file is especially helpful to look at when debugging your program. If your program
has errors, they will be displayed and no output will be generated, otherwise the listing file will
be displayed.
If you prefer a windows integrated programming environment – try the Motorola MCU-EZ
tools. Refer to the MCU-EZ documentation on the disk for more information.
Also, a port for the free GNU C compiler and tools for the HC12 is in the works and may be
finished as you read this. Check www.axman.com or :
http://home.worldnet.fr/~stcarrez/m68hc11_port.html

7
Running your application
After creating an S-Record file you can "upload" it to the development board for a test run.
The provided example “HELLO.ASM” was created to run from RAM so you can use the D-
Bug12 Monitor to test it without programming it into EEPROM.
If you haven’t done so already, verify that the CME-12B/BC board is connected and operating
properly by following the steps under “GETTING STARTED” until you see the D-Bug12
prompt, then follow these steps to run your program:
1. Press and release the RESET button on the CME-12B/BC board. You should see the
PRESS ANY KEY message. Hit the return key ↵to get the monitor prompt.
2. Type LOAD ↵↵
This will prepare D-Bug12 to receive a program.
3. Select Upload or Send and when prompted for a file name select your assembled program
file in s-record format that was created in the previous section called: HELLO.S19
Your program will be sent to the board thru the serial port.
4. When finished loading you will see the > prompt again.
Type CALL 1000 ↵↵
This tells D-Bug12 to execute the subroutine at address $1000, which is the start of our
test program.
5. If everything is working properly you should see the message “Hello World” echoed back
to your terminal screen then, since we return at then end of our program, a line containing
the internal register status displayed by D-Bug12 and a message prompt.
6. If you do not get this message, try going thru this tutorial once more, then if still no go, see
the TROUBLESHOOTING section in this manual
You can modify the hello program to display other strings or do anything you want. The
procedures for assembling your code, uploading it to the board and executing it remain the
same. D-Bug12 has many powerful features such as breakpoints, assembly/disassembly,
memory dump and modify and program trace. Type HELP at the D-Bug12 prompt for a listing
of commands or consult the D-Bug12 documentation on the disk for more information.

8
Programming Flash EEPROM
You can program your application into EEPROM so it executes automatically when you apply
power to the board as follows:
1. Make a backup copy of HELLO.ASM then use a text editor to modify it. Change the start
of the program to $8000 which is the beginning of the EEPROM. Do this by changing the
”ORG $1000” to ”ORG $8000”.
2. Remove the comment ;character from before the following line to initialize the stack
pointer which is necessary when running outside of D-Bug12:
LDS #$C00 ; initialize the stack pointer
3. Add a comment ;character to the beginning of the first RTS statement, which will cause
the program to end gracefully with an endless loop:
; RTS ; return (use this only if called, from monitor
bra ENDPROG ; endless loop
4. Remove the comment ;character from before the following 2 lines at the end, to set the
reset vector to go to the beginning of the program (the label START) when powered on:
org $fffe reset vector
fdb START
5. Re-Assemble HELLO.ASM as described in the "Assembling Source Code" section.
6. Select “CME12BC” under AxIDE.
7. Select the “Program” option and when prompted for a file name, enter the new
HELLO.S19 file then select [OK].
8. Set the CONFIG SWITCH positions 1,2,3,4 and 6 to ON.
9. Press the RESET button on the board then select Continue or hit ENTER. A new utilities
menu should be displayed. If you have trouble here, see the TROUBLESHOOTING
section.
10. Set the CONFIG SWITCH position 5 ON. The red VPP light should come on.
11. When prompted to “Erase” choose Yes.
12. When finished programming, set the CONFIG SWITCH positions 1,2,3,4 and 5 OFF. The
VPP light should turn off.
13. Cycle power or press RESET on the board. Your new program should start automatically
and the “Hello World” prompt should be displayed in the terminal window.
To return to the D-Bug12 monitor program, set the CONFIG SWITCH positions 1,2,3 and 4
back ON then press RESET.

9
MEMORY MAP
Following is the default memory map for this development board. Consult the HC12 technical
reference manual on the support disk for details of the internal memory map for the processor.
FFFF
FFFE RESET Vector Address
8000
- - - - - - - - - - - - - - - - - - - - -
CONFIG SWITCH 1 2 3 4
ON ON ON ON External EPROM U6/7 (Debug12)
ON ON ON OFF External SRAM U4/5
OFF OFF OFF OFF Internal Flash EEPROM
7FFF
1000
External RAM in U4/5 with CONFIG 1 - 4 ON
FFF
D00 HC12 Internal EEPROM
CFF
C00 External RAM in U4/5 with CONFIG 1 - 4 ON
BFF
800 Internal RAM
7FF
400 External RAM in U4/5 with CONFIG 1 - 4 ON
Peripheral Area
3FF
200
Unused = 280-3FF
LCD / CS7 = 270-27F
CS6 = 260-26F
CS5 = 250-25F
CS4 = 240-24F
CS3 = 230-23F
CS2 = 220-22F
CS1 = 210-21F
CS0 = 200-20F
1FF
000 68HC12 Internal Registers
See 68HC12 Technical Reference Manual

10
CONFIG SWITCH
The CME-12B/BC board is shipped from the manufacturer with the following default CONFIG
SWITCH settings:
1234 567 8
ON ON ON ON OFF ON OFF OFF
The 8 position CONFIG SWITCH provides an easy method of configuring the CME-12B/BC32
board operation. Following are the configuration switch descriptions and HC12 I/O port
usage:
CONFIG
SWITCH OPERATION when in ON position HC12 I/O PORT USED
1MODE A selection (see Mode chart
below) MODA / PE5
2MODE B selection (see Mode chart
below) MODB / PE6
3EXT –External Memory enable (1) N/A
4MON –Monitor Memory enable (2) N/A
5VPP - Flash VPP voltage enable N/A
6RXD - Serial Port RXD input enable PS0 / RXD
7PC0 –CAN Port RXCAN enable PC0
8PC1 –CAN Port TX enable PC2
(1) Enables memory bus operation for access to board memory. Expanded bus must be
on for proper operation.
(2) Enables monitor EPROM’s in memory map at 0x8000 – FFFF hex if CONFIG
SWITCH position 3 is also on. When in off position memory space is SRAM for BDM
use.
MODE CHART
Single Chip Mode A and B = OFF
Expanded Wide Mode A and B = ON
MEM-SEL JUMPERS
Memory sockets U4/5 are shipped with 32K byte RAM devices. U6/7 are shipped with 32K
byte EPROM devices programmed with the D-bug12 monitor.
1,3,4 IN: enables RAM or EEPROM, 32K devices to U6/7
1,3 IN: enables RAM or EEPROM, 8K devices in U6/7
2,4 IN: enables EPROM, 8K or 32K devices in U6/7 (Default)