s908gr16ag4cfj Freescale Semiconductor, Inc, s908gr16ag4cfj Datasheet - Page 243

• Manufacturer Part Number: s908gr16ag4cfj
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

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.
A brief description of each monitor mode command is given in
Freescale Semiconductor
Data Returned
3
Wait one bit time after each echo before sending the next byte.
FROM HOST
SENT TO MONITOR
ECHO
Notes:
Description
ECHO
Notes:
4
ECHO
WRITE
1 = Echo delay, approximately 2 bit times
2 = Cancel command delay, 11 bit times
3 = Wait 1 bit time before sending next byte.
FROM HOST
1 = Echo delay, approximately 2 bit times
2 = Data return delay, approximately 2 bit times
3 = Cancel command delay, 11 bit times
4 = Wait 1 bit time before sending next byte.
Operand
Opcode
READ
READ
1
1
WRITE
READ
READ
Table 19-3. READ (Read Memory) Command
Read byte from memory
2-byte address in high-byte:low-byte order
Returns contents of specified address
$4A
3
ADDRESS
4
HIGH
ADDRESS
ADDRESS
MC68HC908GR16A Data Sheet, Rev. 1.0
Figure 19-14. Read Transaction
Figure 19-15. Write Transaction
HIGH
HIGH
1
ADDRESS
1
HIGH
ADDRESS
ADDRESS
Command Sequence
HIGH
HIGH
3
ADDRESS
NOTE
4
LOW
ADDRESS
ADDRESS
LOW
LOW
1
ADDRESS
1
LOW
ADDRESS
ADDRESS
LOW
LOW
Table 19-3
3
DATA
3, 2
1
through
DATA
DATA
DATA
Table
RETURN
4
RETURN
2, 3
Monitor Module (MON)
19-8.
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