Maxim Integrated Secure Microcontroller - Manual (Page 147)

Secure Microcontroller User’s Guide
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Z
Set the security lock. Only the U and Z commands may be given after the security lock is set.
^C
Restarts most operations. N cannot be restarted.
XON/XOFF
These two characters provide flow control to the serial loader. The serial loader never issues them, but
responds to both. XOFF (control-S, DS3, 0x13) requests that character transmission stop. XON (control-
Q, DC1, 0x11) requests the resumption of transmission.
Notes on Selected DS5001FP and DS5002FP Commands
When using the include command ‘I’, certain precautions are needed. The CRCBIT (bit 0) of the CRC
SFR (C1h) must be set or the error message E:NOCRCB is printed. The MSL bit must not be cleared (via
loader) or the error message E:NOTCOD is printed. If the PM bit (bit 1) of the MCON SFR (C6h) is 1,
then CRC_RANGE must be less than or equal to the program range, or else the error message
E:BADRNG is printed.
When storing an end system, it may not be desirable to lithium-back RAM or an RTC. The newness
command ‘N’ accomplishes this. When ‘N’ is issued, the loader prompts with CONFIRM: after the N is
entered. The user must type FRESH without any spaces or deletes and terminate it with a carriage return
to put the part into freshness. The message DID NOT CONFIRM is printed if a mistake is made while
entering FRESH; otherwise the message POWER-DOWN TO MAINTAIN FRESHNESS is printed. The
‘N’ command should be the last function that is executed. After this, the system should be powered down
for storage. At this time, the V
CCO
will be pulled low, removing power from RAM or clock. The newness
command may not be executed when talking through the modem to the serial loader. If it is attempted, the
error message E:ILLCMD is printed.
The DS5001FP and DS5002FP provide loader commands to assist in system checkout. These are ‘G” Get
and ‘P’ Put. Get will read the values of all four I/O ports. Put is used to write a value to a port. This
allows a measure of hardware control while the device is effectively in a reset state. If a port number
other than 0, 1, 2, or 3 is used, the error message E:BADREG is printed. Ports 0 and 2 may not be altered
when talking to the loader through the RPC interface. The error message E:BADREG is printed if it is
attempted. Bits 0 and 1 of port 3 will always be written as ones when port 3 is altered (serial port).
The DS5001FP/DS5002FP write command has more options than the DS5000 version. Any of the
following registers/functions can be initialized using the loader. VAL is written to the requested register.
If an illegal register name is entered, the error message E:BADREG is printed.
CRC
This register selects the range over which a power-on CRC is performed and enables the
process. Only bits 0, 4, 5, 6 and 7 of the CRC register can be altered. Bits 1, 2, and 3 are left
alone.
MCON
Controls range, partition, and peripheral selects. All but bit 0 of the MCON register can be
altered.