I use C6748 dsp to control bq24079's EN2\EN1 pin as shown in the figure. The system is powered with a 3A power supply, current limit is set to 3A.
At first the GPIO1 output 0 and GPIO2 output 1, so the bq24079's EN2EN1=01 and it's in 500mA mode.
Then I use DSP to swith GPIO2 to low, so the bq24079's EN2EN1=00 and it swith into 100mA mode.
But I capture a short-time(<100ns) voltage drop in VCC_BATT which is the output of bq24079, and that makes the DSP disconnected from the emulator.
Q1: Is this normal for bq24079?
Q2: I want to make the system can be powered by a 500mA-USB or by a 1.3A adaptor. How to make the system self-adaptive to the two power supplies?
If I set the EN2EN1=10 and when customer connect the system with a 500mA-USB, the USB's output voltage will drop, which may damage the customrer's USB master devices. But I really want to have a 1.3A charging current when the system is connected to a 1.3A adaptor.
How to realize that?