BQ24296: how to reset bq24296 safe timer

Hi Garrett 

Thanks for your reply.

The usage scenario is that the AC adapter will always be plugged in. After the chip triggers recharging several times, the safety timer will time out, making it impossible to recharge.

I hope that when the recharge is triggered, the safety timer can be reset, rather than the accumulation of several recharges leading to a timeout.

Waiting for your reply.

Thanks

Star

Hi Star, 

What is the total time from start of test until safety timer expires? What safety timer setting (CHG_TIMER in REG05) is the customer using? How are they determining that charge has terminated? 

A simple software workaround would be to reset the timer via toggle of EN_TIMER bit in REG05 every time they detect a recharge. 

Best Regards,

Garrett 

Hi Garrett

Thanks for your help.

The safety timer is 12 hours, which is determined by reading the REG09 register value during an interrupt.

Garrett Kreger said:

A simple software workaround would be to reset the timer via toggle of EN_TIMER bit in REG05 every time they detect a recharge. 

I tried this, but it didn't work.

Thanks

Star

Hi Star, 

Setting the EN_TIMER bit [REG05 bit 3] to 0b then back to 1b has been verified to reset the safety timer.  How are you checking that this method has not worked to reset the timer?

If you are checking REG09 please ensure you are reading it twice in a row to ensure previous fault is cleared. The 2nd read will be any current fault statuses. 

Best Regards,

Garrett 

Hi Garrett

Thanks for your reply.

The customer printed the registration value through irq:

static irqreturn_t bq24296_irq_handler(int irq, void *data)
{
int ret = 0;
u8 data1 = 0,data2 = 0,data3 = 0;

ret = bq24296_read_byte(bq24296_CON9, &data1);
ret = bq24296_read_byte(bq24296_CON8, &data2);
ret = bq24296_read_byte(bq24296_CON9, &data3);
bq_info("bq24296 irq:0x%x,0x%x,0x%x\n", data1,data2,data3);

return IRQ_HANDLED;
}

By looking at the log data,  data3 = 0x30, it is considered that a timeout occurred.

I want to confirm the method of resetting the satety timer. Is there any other method besides writing REG05 bit3?

Waiting for your reply.

Thanks

Star

Hi Star,

We will get back to you by Friday.

Thanks,

Ning.

Hi Star, 

Please see my comments below. 

Thank you for providing customer register read, but it does not provide all the answers, only that REG09 = 0x30 after reading twice. It would be best if customer could perform the following procedure and share the register read data at each step. 1) read REG09 twice in a row 2) write a 0b to REG05 bit 3 3) read REG05 to confirm bit 3 = 0b 4) write a 1b to REG05 bit 3 5) read REG09 twice in a row to check timer fault. 

Star Xu said:

Is there any other method besides writing REG05 bit3?

My initial response to this E2E thread above states 3 methods to reset the safety timer. The 3 methods are also listed in section 9.3.3.5 of the BQ24296 datasheet. 

Best Regards,

Garrett