MC68HC908LJ12 Datasheet, PDF (167/413 Pages) Freescale Semiconductor, Inc – 8-bit microcontroller units

Monitor ROM (MON)
Technical Data
168
Table 10-9. RUN (Run User Program) Command
Description
Operand
Data
Returned
Opcode
Executes PULH and RTI instructions
None
None
$28
Command Sequence
FROM
HOST
RUN
RUN
ECHO
The MCU executes the SWI and PSHH instructions when it enters
monitor mode. The RUN command tells the MCU to execute the PULH
and RTI instructions. Before sending the RUN command, the host can
modify the stacked CPU registers to prepare to run the host program.
The READSP command returns the incremented stack pointer value,
SP + 1. The high and low bytes of the program counter are at addresses
SP + 5 and SP + 6.
SP
HIGH BYTE OF INDEX REGISTER SP + 1
CONDITION CODE REGISTER
SP + 2
ACCUMULATOR
SP + 3
LOW BYTE OF INDEX REGISTER SP + 4
HIGH BYTE OF PROGRAM COUNTER SP + 5
LOW BYTE OF PROGRAM COUNTER SP + 6
SP + 7
Figure 10-7. Stack Pointer at Monitor Mode Entry
Monitor ROM (MON)
MC68HC908LJ12 — Rev. 2.1
Freescale Semiconductor