Part Number: AFE4404
Hello,
What are the mandatory steps to put the IC into Hardware-Power-Down mode?
Here are the steps expected to do the job:
0. Start MCU
1. 200ms sleep (Let the AFE's power supplies settle)
2. Configure RESETZ pin as output(open-drain, RESETZ line has external pull-up 4k7 resistor)
3. Put RESETZ low for 40us (25-50us range).
4. Put RESETZ high for 10ms.
5. Put RESETZ low for 500us (>200us range).
6. Put RESETZ high.
At this point, I expect the device to enter HWPDN mode.
However, this is not happening. The IC still consumes approximately 500µA, and I am still able to read/write registers over I2C after completing these steps.
I verified the RESETZ line continuity by confirming that I2C communication fails when RESETZ is held low, which it does.
Software-Power-Down works as expected, the current consumption drops to ~40uA.
I was able to reproduce that on my custom HW and Heart Rate 5 Click from Microe.
I haven't tested this on AFE4404 EVM.
I even tried to mimic the exact same code as implemented in AFE4404EVM_FW project.
void AFE4404_RESETZ_Init (void);
void AFE4404_Enable_HWPDN (void);
void AFE4404_Disable_HWPDN (void);
void AFE4404_Trigger_HWReset (void);but still with no success.
- Could you share the current consumption graphs while putting the IC into Hardware-Power-Down mode?
- Is there something specific that must be done before that?
- Is Hardware-Power-Down mode working as expected on AFE4404 EVM?
- What HW issue can block entering the HWPDN?
Here is the HW schematic.
RST, CLK, MODE, INT, SCL, SDA lines are directly connected with MCU(nRF52840)
