User’s Manual
M68HC12A4EVB Evaluation Board — Rev. 1
138
D-Bug12 Customization Data
MOTOROLA
D-Bug12 Customization Data
The initial baud register value is 52 (0x0034). At a system clock frequency of
8.0 MHz, this sets the communications rate of 9600 baud.
NOTE:
Because of the ability to choose either SCI0 or SCI1 for use as the control
console, D-Bug12 takes care of initializing the SCI registers. The chosen SCI is
set to eight data bits, one start bit, one stop bit, and no parity.
D.2.7 EEBase and EESize Fields
The
EEBase
and
EESize
fields are used to describe the base address and
range of the M68HC12’s on-chip EEPROM. This information is used by
D-Bug12’s
WriteMem()
function to determine when a byte is being written
to the on-chip EEPROM. D-Bug12 then calls its
WriteEEByte()
function to
place the data in the on-chip EEPROM. On the MC68HC812A4 the EEPROM
base address is mappable to any 4-Kbyte memory space. Therefore, the
EEBase
entry should be only a multiple of 0x1000. The value of
EEBase
is
set to 0x1000 which is the default base address of the on-chip EEPROM for the
MC68HC812A4. The value of
EESize
is also set to 0x1000 (4096) which is
the size of the on-chip EEPROM. Setting the value of
EESize
to 0 disables the
WriteMem()
function’s ability to write to on-chip EEPROM.
NOTE:
It is the responsibility of the startup code to set the base address of the
EEPROM. D-Bug12 does not set or change the EEPROM base address.
D.2.8 EEPROM Erase/Program Delay Function Pointer Field
The
(void)(* Delay)(void)
field is a function pointer that points to an
EEPROM program/erase delay routine. For the MC68HC812A4, the routine
should produce a delay of 20 ms before it returns. The delay routine is nothing
more than a software delay loop. The subroutine is located in the startup code
area of the D-Bug12 EPROM from $FD80 to $FDFF. See
Appendix C.
D-Bug12 Startup Code
.
D.2.9 Auxiliary Command Table Entries
The last two entries in this table provide a mechanism to extend the command
set of D-Bug12. The
AuxCmdTableP
points to an auxiliary command table,
and
AuxCmdCount
contains the number of entries in the auxiliary command
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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