FS26

[m_tarkan]

Hello, I am trying to use FS26 in debug mode however I cannot write and read register correctly. When I look at the debug pin voltage, I saw it is more than 6 volts when I energised the board with 12V. Also, after switch on debug voltage goes to zero. I wonder if it is the reason that I don't get answer without doing wd refresh. Can you help me with this?

[Eason_L]

Hi,

I have the same questions, the circuit is from S32K344 EVB

Eason_L_0-1704936726521.png

1. Accroding to voltage divider, the votage of FS26_VDEBUG is 7.2 (12*15/25), How can it enter debug mode(VDBG(2.5V < debug pin < 6V))?

2. What's the purpose of BJT circuit? It makes debug pin voltage drop to 0V after ~80ms

[diazmarin09]

Hello Eason_L,

In this case, I do recommend you to submit a new case for further information. 

Regards,

David 

[m_tarkan]

Hello David,

OTP mode seems good since the voltage level with the OTP mode configuration is 8.2V. However, when I want it to enter the debug mode directly without entering OTP mode by applying VDBG(2.5V < debug pin < 6V).

m_tarkan_0-1704347546103.png

m_tarkan_1-1704347666961.png

Also, according to database VDBG must be applied continuously. However, when I did the hardaware configuration of the S32K344 eval board for the debug mode, after switch on VDBG goes to zero. At this stage I just want to read and write to the register to see if SPI communication is working properly.

Thank you.

Tarkan

[diazmarin09]

Hello m_tarkan,

Please accept my apologies for the misunderstanding.

To enter in debug mode, it must be applied VDBG (2.5V <Debug pin < 6V) on debug pin prior to apply any voltage to VSUP. When VDBG is applied prior to any VSUP voltage, Debug entry state is passed through and the device starts power up sequence and goes directly to INIT fs state to allow MCU programming or easy debug.

You may follow the procedure below:

diazmarin09_0-1704387610427.png

I hope this information helps.

Regards,

David

[diazmarin09]

Hello m_tarkan,

I hope all is great with you. Thank you for using the NXP communities.

To enter in OTP Mode, the voltage on pin DEBUG must be set at VOTP (7.4V < debug pin < 8.4V) prior to apply any voltage on VSUP pin. -

Could you please make sure the proper level is applied to the DEBUG pin?

I hope this information helps.

Regards,

David