MC68HC908KX8 Datasheet, PDF (262/310 Pages) Motorola, Inc – Microcontrollers

Monitor ROM (MON)
18.10 Commands
The monitor ROM firmware uses these commands:
• READ, read memory
• WRITE, write memory
• IREAD, indexed read
• IWRITE, indexed write
• READSP, read stack pointer
• RUN, run user program
The monitor ROM firmware echoes each received byte back to the PTA0
pin for error checking. An 11-bit delay at the end of each command
allows the host to send a break character to cancel the command. A
delay of two bit times occurs before each echo and before READ,
IREAD, or READSP data is returned. The data returned by a read
command appears after the echo of the last byte of the command.
NOTE: Wait one bit time after each echo before sending the next byte.
FROM
HOST
READ
READ
ADDRESS ADDRESS ADDRESS ADDRESS
HIGH
HIGH
LOW
LOW
4
1
4
1
4
1
3, 2
ECHO
Notes:
1 = Echo delay, 2 bit times
2 = Data return delay, 2 bit times
3 = Cancel command delay, 11 bit times
4 = Wait 1 bit time before sending next byte.
Figure 18-4. Read Transaction
'$7$

RETURN
FROM
HOST
Technical Data
262
WRITE
WRITE
ADDRESS ADDRESS ADDRESS ADDRESS
HIGH
HIGH
LOW
LOW
DATA
DATA
4
1
4
1
4
1
4
1
3, 4
ECHO
Notes:
1 = Echo delay, 2 bit times
3 = Cancel command delay, 11 bit times
4 = Wait 1 bit time before sending next byte.
Figure 18-5. Write Transaction
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
Monitor ROM (MON)
MOTOROLA