Freescale Semiconductor Microcontrollers - Manual (Page 357)

ICS MON08 Interface Connection
Connection Procedure
357 Microcontrollers Debugger Manual
check was successfully passed. If a break character is not received from the
processor, this flag returns an ‘N’. Reasons for this include:
– The baud rate specified was incorrect.
– The processor was not reset properly. Check the Target Hardware Type. If you
are connecting to a class II board, check the MON08 cable communication
connections type in the Advanced Settings dialog box.
• 4 – Device entered monitor mode:
Once the software receives, or fails to receive, a break character from the processor,
it attempts to communicate with the monitor running on the M68HC08 processor. It
tries to read the monitor version number by issuing a monitor mode read. If the
processor fails to respond properly to this command, this flag returns an ‘N’.
• 5 – Reset was Power-On Reset:
If the device properly entered monitor mode (4), the software reads the reset status
register (RSR). This read does not affect the security sequence, and occurs purely for
diagnostic reasons. The RSR indicates the conditions under which the processor
underwent the last reset. For the software to pass the security check properly, it
MUST first cause the processor to undergo a Power-On Reset. The software reads
the RSR to determine if the last reset was indeed caused by power-on. The result of
the RSR read is indicated in parentheses after the flag value. If the highest bit is not
set then the reset was not a power-on reset, and the flag indicates an ‘N’. Reasons for
this include:
– The processor did not power all the way down because power was being supplied
to the processor through either the port pins, IRQ line, RESET line, or power
pins.
– The voltage driven on the power pin of the processor did not go below 0.1 volts.
– The processor was not reset properly. Check the Target Hardware Type. If you
are connecting to a class II board, check the MON08 cable communication
connections type in the Advanced Settings dialog box.
• 6 – ROM is accessible (un-secured):
If the device properly entered monitor mode (4), the software reads locations $FFF6-
$FFFF to determine if the processor passes the security check. Memory locations
which are invalid or protected read back from the device as $AD. If all bytes from
$FFF6-$FFFF read a value of $AD, it is assumed the device is secure, and the flag
value is an ‘N’. If all flags 0-5 register a value of ‘Y’ and flag 6 register a value of
‘N,’ then the reset process has gone correctly except that the security code used to
pass security was incorrect. Specify the correct security code and try again, or
IGNORE the security failure and erase the device. Once you erase a secured device,
you must exit the software and restart it in order to pass security.