Datasheet

NXP Semiconductors

UM11183

KITFS85SKTEVM evaluation board

User manual Rev. 3 — 6 December 2019

32 / 51

7.2.1 Example script: Closing initialization phase, disabling FCCU monitoring

and releasing FS0B

The following script can be used to:

• Disable the WD (simple WD configuration is used here).

• Disable the FCCU monitoring.

On the hardware kit, the FCCU1 is pulled to GND and FCCU2 is pulled to VDDIO,

which is detected as error phase by default. Disabling the FCCU by SPI/I2C avoids

safety issue at startup.

• Close the initialization phase.

• Exit the Debug mode.

• Release FS0B pin. This is valid only if WD is activated in OTP.

Seven good consecutive WD answers are required to have the FLT_ERR_CNTR back

to 0. This is one of the conditions to allow FS0B release.

Table 18. FS85 starting sequence example

Step Register name Value Description

1 FS_WD_WINDOW 0x0200 WDW_WINDOWS[3:0] = 0x0 => Watchdog disabled

2 FS_NOT_WD_WINDOW 0xF50F NOT of FS_WD_WINDOW

3 FS_I_SAFE_INPUTS 0x51C6 FCCU_CFG[1:0] = 0x0 => 0x1 => Monitoring by pair

FCCU12_FLT_POL[0] = 1 => FCCU1 or 2 = 0 is a fault

4 FS_I_NOT_SAFE_INPUTS 0xAC18 NOT of FS_I_SAFE_INPUTS

5 FS_WD_ANSWER 0x5AB2 1st good WD answer (for simple WD selection in OTP)

Close the initialization phase

6 FS_STATES 0x4000 DBG_EXIT[0]=1 => Exit Debug mode

7 FS_WD_ANSWER 0x5AB2 2nd good WD answer

8 FS_WD_ANSWER 0x5AB2 3rd good WD answer

9 FS_WD_ANSWER 0x5AB2 4th good WD answer

10 FS_WD_ANSWER 0x5AB2 5th good WD answer

11 FS_WD_ANSWER 0x5AB2 6th good WD answer

12 FS_WD_ANSWER 0x5AB2 7th good WD answer

13 FS_RELEASE_FS0B 0xB2A5 FS0B pin released (pulled to high level)

14 MFLAG2 0x40F1 Clear flags VSUPUV7; VPREUVL, VSUPUVL, WAKE1FLG

15 FS_OVUVREG_STATUS 0x4550 Clear UV status flags

This sequence can be sent using a script built with FlexGUI. See Section 8.3.2 "Script

sequence files".

7.3 Programming the device with an OTP configuration

The device configuration can be changed three times (see Section 4.2.1 "OTP and

mirrors registers"). The programming steps are exactly the same as the OTP emulation

mode up to step 6.

Then, the user has to burn the part with FlexGUI. See Section 8.4.8 "OTP programming".

Follow the instructions on the screen to proceed.