Hardware and Software Development Tools for the HCS12 - The HCS12/9S12: An Introduction to Software and Hardware Interfacing - page 141

• The serial communication interface (SCI) function supports the EIA232
standard. A microcontroller demo board would use this interface to communicate
with a PC.
• The serial peripheral interface (SPI) function is a synchronous interface that
requires a clock signal to synchronize the data transfer between two devices. This
interface is mainly used to interface with peripheral chips such as shift registers,
seven-segment displays and LCD drivers, A/D and D/A converters, SRAM and
EEPROM, phase-locked-loop chips, and so on. All of these devices must have the
SPI interface.
• The inter-integrated circuit (I 2 C) is a serial interface standard proposed by Phillips.
This interface standard allows microcontrollers and peripheral devices to exchange
data.
• The byte data link communication (BDLC) module was proposed for low-speed
data communication in automotive applications. It provides access to an external
serial communication multiplexed bus that operates according to the SAE J1850
protocol.
• The controller area network (CAN) was proposed to be used mainly as a vehicle
serial data bus to provide reliable operation in the EMI environment and achieve
the high bandwidth required in that environment.
The MC9S12DG256-based demo board Dragon12-Plus from Wytec is recommended for
learning the HCS12 microcontrollers.
Software development tools include the text editor, the terminal program, the cross assem-
bler, the cross compiler, the simulator, the source-level debugger, and the integrated develop-
ment environment (IDE). A sophisticated IDE should contain a text editor, a terminal program,
a cross compiler, a cross assembler, and a source-level debugger. It allows the user to perform all
the development work without leaving any program.
In this text, we use the freeware from Mgtek and CodeWarrior from Freescale to enter and
test all the assembly programs. Tutorials on how to use MiniIDE and CodeWarrior IDE are pro-
vided. The debugging activities on a demo board are facilitated by the command set provided by
the D-Bug12 monitor.
The D-Bug12 monitor has four modes.
• EVB mode. Most users use this mode to perform development and evaluation
work.
• POD mode. This mode allows one to use the demo board to debug another HCS12
target board.
• Jump-to-EEPROM mode. This mode allows the user to run the application
programmed into the on-chip EEPROM after power-up or reset.
• Bootloader mode. This mode allows the user to update the D-Bug12 monitor or
program the application code into the flash memory out of reset or after being
powered on.
The only freeware source-level debugger is the limited version of CodeWarrior from
Freescale. CodeWarrior requires a demo board to be programmed with the 2-kB serial monitor
from Freescale or connected to a BDM-based debug adapter.