DS1963S

8 of 37

DS1963S MEMORY MAP (continued) Figure 5

Counter Memory with User Read Access Only

Page #

Address Range

Description

19

0260h to 0263h

Counter 0 (Write Cycles to Page 8)

0264h to 0267h

Counter 1 (Write Cycles to Page 9)

0268h to 026Bh

Counter 2 (Write Cycles to Page 10)

026Ch to 026Fh

Counter 3 (Write Cycles to Page 11)

0270h to 0273h

Counter 4 (Write Cycles to Page 12)

0274h to 0277h

Counter 5 (Write Cycles to Page 13)

0278h to 027Bh

Counter 6 (Write Cycles to Page 14)

027Ch to 027Fh

Counter 7 (Write Cycles to Page 15)

20

0280h to 0283h

Write Cycle Counter Secret 0

0284h to 0287h

Write Cycle Counter Secret 1

0288h to 028Bh

Write Cycle Counter Secret 2

028Ch to 028Fh

Write Cycle Counter Secret 3

0290h to 0293h

Write Cycle Counter Secret 4

0294h to 0297h

Write Cycle Counter Secret 5

0298h to 029Bh

Write Cycle Counter Secret 6

029Ch to 029Fh

Write Cycle Counter Secret 7

21

02A0h to 02A3h

PRNG Counter

ADDRESS REGISTERS Figure 6

Target Address (TA1)

T7T6T5

T4T3T2T1T0

Target Address (TA2)

T15

T14

T13

T12

T11

T10

T9

T8

Ending Address with

Data Status (E/S)

(Read Only)

AA

0

PF

E4E3E2E1E0

WRITING WITH VERIFICATION

To write data to the DS1963S, the scratchpad has to be used as intermediate storage. First the master

issues the Write Scratchpad command to specify the desired target address, followed by the data to be

written to the scratchpad. Under certain conditions (see Write Scratchpad command) the master will

receive an inverted CRC16 of the command, address and data at the end of the write scratchpad command

sequence. Knowing this CRC value, the master can compare it to the value it has calculated itself to

decide if the communication was successful and proceed to the Copy Scratchpad command. If the master

could not receive the CRC16, it should send the Read Scratchpad command to verify data integrity. As

preamble to the scratchpad data, the DS1963S repeats the target address TA1 and TA2 and sends the

contents of the E/S register. If the PF flag is set, data did not arrive correctly in the scratchpad. The

master does not need to continue reading; it can start a new trial to write data to the scratchpad. Similarly,

a set AA flag indicates that the device did not recognize the Write command. If everything went