DS1205S

021798 3/17

COMMAND WORD STRUCTURE Figure 2

(KK)

MSB

LSB

(AAAAAA)

FFFFFFFF

(KK) =

Two-bit number specifying which partition is to be accessed. 00 specifies subkey 0. 01 specifies

subkey 1. 10 specifies subkey 2. 11 specifies the scratchpad.

Complement of (KK) on a bit-by-bit basis. If the numbers are not complements the command

word is invalid and no action will be taken.

(AAAAAA) =

Address field containing address bits that define the starting byte address of the partition to be

accessed.

Complement of (AAAAAA) on a bit-by-bit basis. If the numbers are not complements the com-

mand word is invalid and no action will be taken.

FFFFFFFF =

Function code field. Specifies the action to be taken.

LOCATIONS, AND FUNCTION CODES FOR EACH COMMAND WORD Figure 3

COMMAND

VALID PARTITION

CODE KK

VALID BYTE

ADDRESS AAAAAA

VALID FUNCTION

CODE FFFF FFFF

Set Scratchpad

11

0 - 63

1001 0110

Get Scratchpad

11

0 - 63

0110 1001

Set Secure Data

00, 01, 10

16 - 63

1001 1001

Get Secure Data

00, 01, 10

16 - 63

0110 0110

Set Security Match

00, 01, 10

000000

0101 1010

Move Block

00, 01, 10

000000

0011 1100

SECURE PARTITION COMMANDS

Each of the three secure partitions within the DS1205S

MultiKey is comprised of a 64-bit I.D. field, a 64-bit secu-

rity match code and a 384-bit secure data field (Figure

4). The three commands that operate on the secure

partitions are:

1) Set Security Match

2) Set Secure Data

3) Get Secure Data

As a guard against attackers, the security match code

can never be read. Similarly, tampering through repro-

gramming will immediately clear the entire secure parti-

tion.

SECURE PARTITION ORGANIZATION Figure 4

ID FIELD

SECURITY MATCH FIELD

SECURE DATA FIELD

64 BITS

384 BITS

64 BITS

07

8

15

16

63

BYTES