Programming sequence

PM0064

8/13

Doc ID 16274 Rev 3

3.3

Option programming

1.

Programming mode entry (State_1): Follow steps to enter programming mode as in

Table 2.

2.

Option register write (State_2) writes the value of the options that must be programmed

into the Option register. See Table 4: Option programming (State_2).

3.

Option programming (State_4) is the first stage to program the options that were

programmed into the Option register. See Table 5: Option programming (State_4).

4.

Option programming (State_6) is the second stage of programming the options. See

Table 6: Option programming (State_6).

Note:

The reserved Option bits must not be altered (one way to ensure they are not altered is to

set them to 0 regardless of their value).

Refer to the STM8T141 datasheet for the position of the reserved Option bits.

Table 4.

Option programming (State_2)

Step

Action

Explanation

1.

CS = HIGH

CS = 1 required for transition from State_1 to State_2.

2.

CX - 1 double clock

Clock IC into State_2.

3.

Make OUT an output

In State_2 OUT is an IC input, data can be written to it by the

programmer.

4.

OUT = LOW

Place a 0 on OUT.

5.

CX - 1 double clock

Clock in the 0 on OUT to prepare the register.

6.

OUT = option bit value

Place the value for option_0 on OUT.

7.

CX - 1 double clock

Clock in option value.

8.

Repeat Steps 6 and 7 for

all options except

option_15.

Clock in all the options until option_14 is clocked in, leaving only

option_15 not yet clocked into the register.

9.

CS = LOW

The final option is written to the register while moving into

State_3.

10.

OUT = option_15

Place the final option on OUT.

11.

CX - 1 double clock

Clock in option_15; this automatically clocks the IC into State_3.

12.

Tri-state OUT pin

Any controller attached to the IC's OUT must be tri-stated.

Table 5.

Option programming (State_4)

Step

Action

Explanation

1.

CS = HIGH

CS = 1 required for transition from State_3 to State_4.

2.

CX - 1 double clock

Clock IC into State_4.

3.

VDD = 6.7 V

Increase power for IC up to 6.7 V

4.

Wait 1 ms.

Wait for voltage to stabilize at 6.7 V

5.

CX - 1 double clock

Signal for IC to program options.

6.

CX = LOW

CX = 0 to prevent false signal when VREG is raised later on.