Motorola M68EVB912B32 User Manual page 43

configures D-Bug12 for operation with the selected target device. The default device list
contains entries for the MC68HC912B32 and the MC68HC812A4. The table below shows the
command line name to use for the two default MCU devices.
Entering the DEVICE command followed by a device name and seven hexadecimal parameters
allows new devices to be added to the target device table or existing device table entries to be
modified. When a new device is added or when an existing device entry is modified, it becomes
the currently selected device. If a new device does not contain a particular on-chip resource, such
as Flash EEPROM, a value of zero should be entered for the starting and ending addresses
Because the target device data and the current device selection are stored in the probe MCU's on-
chip EEPROM, new device information and the device selection are retained when power is
removed from the POD. If the M68EVB912B32 is operated in EVB mode and the contents of
any locations of the on-chip EEPROM are altered it is strongly recommended that the on-chip
EEPROM be completely erased by using the BULK command before using the EVB in POD
mode again. Erasing the on-chip EEPROM causes D-Bug12 to reinitialize the device table with
the two default MCU devices. The information for any new devices that were added to the table
will be lost.
restrictions:
When operating the M68EVB912B32 in EVB mode, the DEVICE command may only be used to
display the current device information.
The DEVICE command maintains a 16-bit checksum on the contents of the entire on-chip
EEPROM to maintain the integrity of the device table. If any of the on-chip EEPROM locations
are altered while operating the M68EVB912B32 in EVB mode, D-Bug12 will reinitialize the
device table with the default device information contained in the on-chip Flash EEPROM.
However, it is possible for the checksum verification to fail (one case where the checksum will
fail is if the entire contents of the on-chip EEPROM is programmed with zeros). Therefore, it is
strongly recommended that the on-chip EEPROM be completely erased by using the BULK
command before using the EVB in POD mode again. Using the EVB in Probe mode with a
corrupt device data table may cause D-Bug12 to operate in an unpredictable manner.
The 768 bytes of on-chip EEPROM allows a total of 34 entries in the device table. Do not
exceed this number.
When adding a new device to the device table, the addresses provided for the on-chip Flash
EEPROM, on-chip RAM and the I/O Registers should reflect the locations of these resources
when the part is reset. This requirement is necessary for the FBULK and FLOAD commands to
work properly.
68EVB912B32UM/D
Device Name Target MCU
912B32 MC68HC912B32
812A4 MC68HC812A4
OPERATION
3-21