NXP 5744P LDT Function

[rehabhsn]

I tried to configure the LDT function to fs65LdtFunc5 and read the value of wakeup 

FS65_M_LDT_WAKE_UP_1_ADDR , FS65_, FS65_M_LDT_WAKE_UP_2_ADDR  M_LDT_WAKE_UP_3_ADDR 

to know the sleep time after wakeup 

but i have a question regarding the overflow after 6 month will cause the ecu to wakeup , how to test this feature ? is there any flag for the overflow, or how could i preload the counter with a specific value to reach the overflow fast ? 

[TomasVaverka]

Hi Rehab,

After a POR of the device, the LDT is in idle mode waiting for configuration. The after-run timer function starts when the LDT_ENABLE bit is set by SPI. The wake-up timer function starts when the device enters in LPOFF mode. Then when function 5 is selected and the counter overflows (OVRFLW), the device wakes up and the counter is stopped. The counter must be disabled (~ENABLE) before reading its value and enabled again. Overflow means counter max value is reached (all 24 bits at “1”).

Please note that LDT function 5 principle (software flow) is shown in the AN5238, page 43:

https://www.nxp.com/products/power-management/pmics-and-sbcs/system-basis-chips/grade-1-and-grade-0-...

BR, Tomas

[rehabhsn]

When overflow happens, ecu wake up and counter will be the max value so I can read it with its max value after disable  (~ENABLE) , correct? 
I can't find the document you mention it.

[TomasVaverka]

Hi Rehab,

Yes, your understanding is correct.

The AN5238 is classified as a Secure File requiring an NDA.

If your company has not signed the NDA with NXP yet, you can request it from:
https://www.nxp.com/support/support:SUPPORTHOME

If there is a valid NDA in place, you can download it from the website I shared before.

Please make sure you are signed in to nxp.com. If you do not see the AN5238, please click on "Request additional access" or edit your secure access rights by going to My NXP > Profile. 

For more information about secure access rights, please refer to this website:
https://www.nxp.com/support/support/secure-access-rights:SEC-ACCESS

Hope this helps.

BR, Tomas

[rehabhsn]

@TomasVaverka  any help regarding this issue