LP87702-Q1: About Watchdog Setting Issue

yimin bai34

Genius 4755 points

Part Number: LP87702-Q1

Hi SIr

For Watchdog Setting question

1. if we follow the OTP setting and use enable CLKIN (GPO2) pin to activate Watchdog function .

http://www.ti.com/lit/df/tidrye2/tidrye2.pdf

2. in Spec Figure 14. Watchdog Operation, it seems we need to send Long Open signal to PMIC after enabling WD (set CLKIN (GPO2) low)

http://www.ti.com/lit/ds/symlink/lp87702-q1.pdf

Question:

in HW design , we set CLKIN pin low(resistor to GND) to enable WD. After power-on, CPU starts to work and then send signal to WDI.

What is the min. time between enabling WD and Send Long-open signal ? if over the time , LongOpenTime expire ?

please advise

Yimin

over 6 years ago

0 yimin bai34 over 6 years ago

Genius 4755 points

Hi SIr

Any update

0 Tuomo Alatalo over 6 years ago in reply to yimin bai34

TI__Intellectual 950 points

Hi Yimin,

Sorry for the late reply, I've been last few weeks on my summer vacation.

About the WD, after OTP read has been completed approximately 1.2ms device goes to LONG_OPEN_TIME and start to seek WDI pulse. This is same situation if WD disabled and then enabled again = LONG_OPEN_TIME start and WDI pulse seek. If WDI not exist, WD expired. Watchdog expiration always causes a reset pulse at WD_RESET output

Regards

Tuomo

Power management

Power management forum

LP87702-Q1: About Watchdog Setting Issue