STUSB4710AQ1TR production programming, and discharge

[thutch]

Hi there,

 

I have two questions on moving forward with a STUSB4710 in a 5k EAU project. 

 

1. Do you have recommendations on a setup to program the NVM in a CM environment? Likely this involves custom firmware based on the project recommended in the NVM flashing tutorials in some of the presentations I've seen? Is there a straightforward way to load this into an existing STM32L474 project and use the I2C interface to update the NVM? Any tutorials or information on this?

2. The STUSB4710 seems to take a long time to discharge the output node, so that it's 30 seconds or so after a detatch event before it will re-establish power connection with the tablet. Is this expected even after playing with the discharge settings in the configurator? I will look to grab some timing scope captures early next week when I have new hardware in hand.

 

Thanks!

[thutch]

Here are a couple of screenshots of the behavior. A disconnect of the USB-C PD sink followed by an immediate reattach takes >10s to re-enable. This is the measurement of Vbus over time.

 

From the datasheet, I expected the default behavior to be around 840ms. This is on a custom design though the schematic was lifted from STEVAL ISC004V1. I assume this is more likely the sink device not properly discharging its own capacitance which prevents the STUSB from re-enabling?

 

[Didier HERROUIN]

Hello,

The captures have been made on SINK side, haven't they ?

If this is the case, the discharge time can not be impacted by the STUSB4710 and you are right, this is probably linked to the discharge circuit of the Sink device (the threshold is usually around 0.6V).