DocID018532 Rev 3

11/13

PM0083

Software interface

2.7

Programming the option bytes

2.7.1

Programming mode entry

Follow the steps described in Section 2.4: Programming mode entry on page 7.

2.7.2

Option set-up and programming

Options are programmed one byte at a time.

Table 9. Option programming procedure

Step

Action

Description

1.

Write 0x40

0x40 is the command to be given before writing data.

2.

Write 0x0F

0x0F is the option loop address.

3.

Write 0x04

Write number of program steps (4).

4.

Write 0x30

0x30 is the command to be given before reading data.

5.

Write 0x0F

0x0F is the option loop address.

6.

Read

Read data

7.

Reply = 0x04?

If the result is 4 (number of program steps written in step 3) then

the device has accepted the data.

8.

Write 0x60

Issue option program command.

9.

Write option byte

Write data to the selected option byte.

10. VDD = 6.5 V

Raise supply voltage to 6.5 V

11. Write 0x2i (i = 0, 1 or 2)

Send the option byte number ( i ) ORed with instruction 0x20.

12. Wait 40 ms

Wait 40 ms for option programming.

13. Write 0xAi(i = 0, 1 or 2)

Send the option byte number ( i ) ORed with instruction 0xA0.

14. Wait 40 ms

Wait 40 ms for option programming.

15. Write 0xEi (i = 0, 1 or 2)

Send the option byte number ( i ) ORed with instruction 0xE0.

16. Wait 40 ms

Wait 40 ms for option programming.

17. Write 0x0i (i = 0, 1 or 2)

Send only the option byte number.

18. VDD = 5.0 V

Lower supply voltage to normal operating voltage again.

19.

Repeat steps 1 to 18 for

option bytes 1 and 2.

Each option byte's status (for 8 option bits) is written in the same

manner.

Note: Option bytes are programmed in the following order: byte0,

byte1 and byte2.

20. Device power OFF

VDD = 0 V