MC68HC08AS32A Datasheet, PDF (272/296 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Development Support
17.3.1.5 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
DATA
4
ECHO
Notes:
1 = Echo delay, approximately 2 bit times
2 = Data return delay, approximately 2 bit times
RETURN
3 = Cancel command delay, 11 bit times
4 = Wait 1 bit time before sending next byte.
Figure 17-10. Read Transaction
FROM
HOST
WRITE
WRITE
ADDRESS ADDRESS ADDRESS ADDRESS
HIGH
HIGH
LOW
LOW
DATA
DATA
3
1
3
1
3
1
3
1
2, 3
ECHO
Notes:
1 = Echo delay, approximately 2 bit times
2 = Cancel command delay, 11 bit times
3 = Wait 1 bit time before sending next byte.
Figure 17-11. Write Transaction
A brief description of each monitor mode command is given in Table 17-3
through Table 17-8.
Data Sheet
272
Development Support
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MC68HC08AS32A — Rev. 1
MOTOROLA