Datasheet

Monitor ROM (MON)
Technical Data MC68HC908LJ12 — Rev. 2.1
172 Monitor ROM (MON) Freescale Semiconductor
Figure 10-9. Data Block Format for ROM-Resident Routines
The control and data bytes are described below.
• Bus speed — This one byte indicates the operating bus speed of
the MCU. The value of this byte should be equal to 4 times the bus
speed. E.g., for a 4MHz bus, the value is 16 ($10). This control
byte is useful where the MCU clock source is switched between
the PLL clock and the crystal clock.
• Data size — This one byte indicates the number of bytes in the
data array that are to be manipulated. The maximum data array
size is 255. Routines EE_WRITE and EE_READ are restricted to
manipulate a data array between 2 to 15 bytes. Whereas routines
ERARNGE and MON_ERARNGE do not manipulate a data array,
thus, this data size byte has no meaning.
• Start address — These two bytes, high byte followed by low byte,
indicate the start address of the FLASH memory to be
manipulated.
• Data array — This data array contains data that are to be
manipulated. Data in this array are programmed to FLASH
memory by the programming routines: PRGRNGE,
MON_PRGRNGE, EE_WRITE. For the read routines: LDRNGE,
MON_LDRNGE, and EE_READ, data is read from FLASH and
stored in this array.
DATA SIZE (DATASIZE)
START ADDRESS HIGH (ADDRH)
START ADDRESS LOW (ADDRL)
DATA 0
DATA 1
BUS SPEED (BUS_SPD)
FILE_PTR
DATA N
DATA
ARRAY
$XXXX
DATA
BLOCK
ADDRESS AS POINTER
RAM