I want to force the chip to enter Shutdown mode.
From the TRM:
The bq20z40-R1/bq20z45-R1 enters Shutdown mode if the following conditions are met:
• [SHUTV] in Operation Cfg C is set to 0 AND Voltage ≤ Shutdown Voltage AND Current ≤ 0 for a period of 10 s
OR
• [SHUTV] in Operation Cfg C is set to 1 AND Min(CellVoltage4..1) ≤ Cell Shutdown Voltage AND Current ≤ 0 for a period of 10 s
OR
• (ManufacturerAccess shutdown command received AND Current = 0) AND PackVoltage < Charger Present threshold.
I am trying to work with the third case, where I send 0x0010 (shutdown) to MAC (0x00) twice. But the criterion makes no sense to me, possibly because I just don't understand something.
My pack is fully charged (8242 mV). Charger Present is at its default of 3000 mV. Therefore, PackVoltage > Charger Present threshold. I can't get it to shut down, the command seems to be ignored.
This is an embedded system (that is, PRES pin is pulled low and NR is set).
I *can* get it to shut down if I first turn off the FETs so that the Pack pin is at 0. Then the command works. But that can't be the way to do this?
What am I missing?
Thanks
Ed K
