Tips and Suggestions

Following are a number of tips, suggestions and answers to common questions that will solve many problems users have with the CME-12B/BC development system. You can download the latest software from the Support section of our web page at:

www.axman.com

Utilities

∙If you’re trying to program memory or start the HC12 Utilities, make sure all jumpers and CONFIG SWITCH settings are correct.

∙Be certain that the data cable you’re using is bi-directional and is connected securely to both the PC and the board. Also, make sure you are using the correct serial port.

∙Make sure the correct power is supplied to the board. You should only use a 9 volt, 300 mA adapter or power supply. If you’re using a power strip, make sure it is turned on.

∙Make sure you load your code to an address space that actually exists. See the Memory Map if you’re not sure.

∙Make sure you're not over-writing memory used by the monitor program.

∙If you’re running in a multi-tasking environment (such as Windows™) close all programs in the background to be certain no serial conflict occurs.

Code Execution

∙Make sure the CONFIG SWITCH is set for the proper mode. If executing from the BDM, you should turn switches 1-4 OFF. If debugging from internal flash EEPROM, disable any reset macro’s.

∙If you’re using D-Bug12 breakpoints may not be acknowledged if you use the CALL command. You should use one of the GO command instead.

∙Check the HC12 reset vector located at FFFEh - FFFFh. These 2 bytes contain the address where execution will begin when the unit is powered on.

∙When running your code stand-alone, you must initialize ALL peripherals used by the micro, including the Stack, Serial Port, etc.

∙You must either reset the COP watchdog timer in the main loop of your code or disable it when not running under MBug or BDM mode. The micro enables this by default and if you don't handle it your code will reset every couple of ms.

ImageCraft C

∙Your make or build should create a .MAP file. Some versions change this to a .MP file. At the top of this file should be a label __START. This is where you should CALL or GO to when debugging in D-Bug12.

16

Page 15 Page 17
Page 16
Image 16
Motorola 68HC12B32, 68HC12BC32, CME-12B/BC manual Tips and Suggestions, Utilities
Page 15 Page 17

68HC12B32, CME-12B/BC, 68HC12BC32 specifications

The Motorola 68HC12BC32, CME-12B/BC, and 68HC12B32 are microcontroller units (MCUs) that are part of the renowned HC12 series, which gained popularity in embedded system designs due to their versatility, robust performance, and comprehensive feature set. These MCUs are widely used in automotive applications, industrial control systems, and various consumer electronics due to their advanced capabilities.

One of the main features of the 68HC12BC32 is its 16-bit architecture, which allows for efficient processing and greater precision in calculations compared to 8-bit counterparts. This feature is crucial for applications requiring high-performance processing, such as real-time control systems. The processor operates at clock speeds of up to 25 MHz, providing the computational power necessary for complex operations.

The 68HC12MCUs include various on-chip memory options, such as ROM, RAM, and EEPROM. For instance, the 68HC12BC32 comes with up to 32 KB of ROM and 1 KB of RAM, along with 512 bytes of EEPROM, making it suitable for applications that require data retention even when the power is turned off. The presence of on-chip memory significantly reduces the need for external components, simplifying system design and enhancing reliability.

Moreover, these microcontrollers feature a rich set of input/output (I/O) capabilities, including multiple general-purpose I/O lines, timer/counter modules, and analog-to-digital converters (ADCs). The integration of these components allows for flexible interfacing with a multitude of sensors and actuators, enabling designers to create sophisticated applications without needing extensive external circuitry.

The embedded communication interfaces, such as SPI (Serial Peripheral Interface), I2C (Inter-Integrated Circuit), and CAN (Controller Area Network), are vital for enabling communication between devices in multiprocessor systems. This capability is particularly beneficial in automotive applications, where seamless data exchange is critical for tasks such as engine control and diagnostics.

Power management features in the 68HC12 series enhance its suitability for battery-powered applications. The ability to enter low-power modes helps extend battery life, making these microcontrollers ideal for portable devices.

In summary, the Motorola 68HC12BC32, CME-12B/BC, and 68HC12B32 microcontrollers are robust and flexible MCUs that offer a combination of advanced processing capabilities, extensive memory options, versatile I/O functionality, and efficient communication interfaces. These characteristics make them well-suited for various applications, from automotive and industrial systems to consumer electronics, ensuring they remain relevant in the evolving landscape of embedded technology.
Top Page Image Contents