Figure 6-2. Target Address (TA1)

7

6

5

4

3

2

1

0

T7

T6

T5

T4

T3

T2

T2

T0

Figure 6-3. Target Address (TA2)

7

6

5

4

3

2

1

0

T15

T14

T13

T12

T11

T10

T9

T8

Figure 6-4. Ending Address with Data Status (E/S) (Read Only)

7

6

5

4

3

2

1

0

AA

0

PF

E4

E3

E2

E1

E0

6.3.4 Writing Data to the FRAM

The TMF0064 device does not allow writes to the FRAM memory directly by the host. Achieve writing to the

FRAM memory directly by the host by using the scratchpad as an interim repository. To write into the scratchpad,

the host first issues the Write Scratchpad command followed by the desired target address and the data to write

into the scratchpad. Depending on the conditions the Write Scratchpad Command section describes, the host

can receive an inverted CRC16 of the entire write scratchpad sequence (the write scratchpad is commanded,

the address and the data) at the end of the Write Scratchpad command sequence.

If the host receives the CRC16 value, the host can compare the received value to the expected computed

value. If there is a match, the write scratchpad communication is successful and the host decides on whether to

proceed to the Copy Scratchpad command.

If the host does not receive the CRC16 value, then the host can use the Read Scratchpad command to verify

integrity of the data stored in the scratchpad. After receiving the Read Scratchpad command, the TMF0064

initially transmits the contents of the target address registers (TA1, TA2) and the E/S register. If the PF flag is

set, or if the AA flag is set but PF flag cleared, the previous Write Scratchpad command is not successful. In

this case, the host can terminate the Read Scratchpad sequence and start another attempt to write data to the

scratchpad. If the previous Write Scratchpad is successful, both flags are cleared and the E[4:0] that is read

indicates the address of the last byte written to the scratchpad. In this case, the host can continue reading from

the TMF0064, verifying all the data bytes. If there is a match, the host can send the Copy Scratchpad command

followed by the exact data of the registers TA1, TA2, and E/S that the host obtained by reading the scratchpad.

At the end of the Copy Scratchpad sequence, if the authorization pattern matches, the TMF0064 starts copying

the scratchpad data to the requested location, provided copy protection is not set, the PF flag is cleared, and

there are no Read Memory or Extended Read Memory commands issued between Write and Copy Scratchpad

commands.

6.3.5 TMF0064 Device ID

The 64-bit ID identifies each TMF0064. The 48-bit serial number is unique and programmed by Texas

Instruments.

8b CRC

48-BIT SERIAL NUMBER

8b FAMILY CODE

MSB

LSB MSB

LSB MSB

LSB

Figure 6-5. 64 bit factory programmed EPROM

6.3.6 Bus Termination

The drive output of the TMF0064 is an open-drain, N-channel MOSFET. For proper operation, connect a 500Ω

external pull-up resistor on the SDQ bus (see Figure 7-1).

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TMF0064

SLVSJQ6 – SEPTEMBER 2025

Copyright © 2025 Texas Instruments Incorporated

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