14.4.2 Secure SAM-BA Monitor

Secure SAM-BA Monitor restricts the number of supported commands compared to the non-secure SAM-BA Monitor. Direct read and write access to the system memory is now discarded and new commands are introduced to help the user configure the Secure boot mode.

Note that the syntax of commands differs from that of the non-secure SAM-BA Monitor.

Commands are the only transfers using the raw text format. All other transfers, including replies and payloads, use the Xmodem protocol.

The syntax for Secure SAM-BA Monitor commands is:

command ::= op_code “,” address “,” length “,” id “,” rw “#”

op_code ::= “RVER” | “WCKY” | “SAPT” | “SMBX” | “RMBX” | “EAPP” | “SFIL” | “RFIL” | “SJTD” | “CRST” | “SSEC” | “SSNM”

address ::= hex_value

length ::= hex_value

id ::= hex_value

rw ::= hex_value

hex_value ::= [ hex_digit ] | hex_digit hex_value

hex_digit ::= “0” | “1” | “2” | “3” | “4” | “5” | “6” | “7” | “8” | “9” | “A” | “B” | “C” | “D” | “E” | “F” | “a” | “b” | “c” | “d” | “e” | “f”

The op_code parameter is always a string of four upper-case letters. The address and length parameters must not exceed eight hexadecimal digits.

The id and rw parameters are not used but kept for backward compatibility purpose. They should be left empty.

Depending on the command, a data payload can be added after the command. In this case, the payload must be sent after the Secure SAM-BA Monitor has acknowledged the command and communicated how the data payload must be split (size of the payload).

The following array lists all supported commands and their expected parameters:

There are three types of Secure SAM-BA command replies. The first type is used as a Command ACKnowledge for all but EAPP and SVER commands. In this case, the syntax of the reply is:

reply ::= “CACK,” errcode “,” length “#” [ payload ]

errcode ::= hex_value

length ::= hex_value

hex_value ::= [ hex_digit ] | hex_digit hex_value

hex_digit ::= “0” | “1” | “2” | “3” | “4” | “5” | “6” | “7” | “8” | “9” | “A” | “B” | “C” | “D” | “E” | “F” | “a” | “b” | “c” | “d” | “e” | “f”

payload ::= [ BYTE ]| BYTE payload

The second type replies to EAPP (Execute APPlet) commands. The syntax of this reply is the same as the first type except that “CACK” is replaced by “ASTA”, which stands for Applet STAtus.

Finally, the third type replies to RVER (Read VERsion) commands. . The syntax of this reply is the same as the first type except that “CACK” is replaced by “SVER”, which stands for Send VERsion.