DRA821U-Q1: Linux reboot every 13 minutes even PMIC A's WD_RST_EN bit is written to 0.

Part Number: DRA821U-Q1
Other Parts Discussed in Thread: DRA821

Tool/software:

Hi there,

Like DRA821 evaluation board, our design uses two PMICs TPS6594141B and LP876441B1 to power DRA821. Software wise, we use Linux PSDK v10.0.1.

 We tried to test TPS6594 watchdog Q&A mode. 

TestCase: Enable watchdog, but disable WD_RST_EN. 

Do not feed watchdogexpect the interrupt signal nINT,  the SoC does not reset

Result: After about 13mins(Long window), the SoC reset.

 

TPS6594 (with DRA821)watchdog Q&A mode

We executed following:

 

1.disable wdg

 i2cset -f -y -m 0xe0 1 0x48 0x31 0x20  //GPIO1 -> i2c

 i2cset -f -y -m 0xe0 1 0x48 0x32 0x40  //GPIO2 -> i2c

 i2cset -f -y -m 0x04 0 0x12 0x06 0x04  //PWRHOLD=1

 i2cset -f -y -m 0x40 0 0x12 0x09 0x00 //disable wdg

 

2.config wdg

 i2cset -f -y -m 0x02 0 0x12 0x06 0x02 //set Q&A mode

 i2cset -f -y -m 0x38 0 0x12 0x09 0x38 //set fail_th 

 i2cset -f -y -m 0x07 0 0x12 0x09 0x05   //set rst_th  

 i2cset -f -y -m 0x80 0 0x12 0x09 0x00 //disable reset WD_RST_EN

 

3.check registers

 i2cget -f -y 0 0x12 0x01

 i2cget -f -y 0 0x12 0x02

 i2cget -f -y 0 0x12 0x03

 i2cget -f -y 0 0x12 0x04

 i2cget -f -y 0 0x12 0x05

 i2cget -f -y 0 0x12 0x06

 i2cget -f -y 0 0x12 0x07

 i2cget -f -y 0 0x12 0x08

 i2cget -f -y 0 0x12 0x09

 i2cget -f -y 0 0x12 0x0a

 gpioget -c 0 84  //PMIC nINT moniter

 

4.enable wdg

 i2cset -f -y -m 0x40 0 0x12 0x09 0x40 //enable WDG

 i2cset -f -y -m 0x04 0 0x12 0x06 0x00 //pwrhold = 0

Do you see any mistakes/reasons causing the system reboot every 13 minutes?

Thanks,

Charles