2024-02-29, 09:19 PM
We will probably ship the next few batches with some cover or dummy plug to prevent mistakes like this.
Still thinking about a future circuit revision that makes this mistake less catastrophic. The issue is, that when plugging an Ethernet device into that port while the MacArthur HAT is powered from 12V, the pin where MAIANA excpects 12v will loop back to the pin where MAIANA expects the AIS TX switch. This blows up an ESD protection diode on the MacArthur HAT. The tricky thing is, to apply a fix that's not interfering with the functionality of MAIANA. Increasing the working voltage of the ESD diode from 3.3V to >12V is my current favorite.
Meanwhile, people that already have a MacArthur HAT can make their own dummy plugs by cutting off the connector from an old network cable.
Still thinking about a future circuit revision that makes this mistake less catastrophic. The issue is, that when plugging an Ethernet device into that port while the MacArthur HAT is powered from 12V, the pin where MAIANA excpects 12v will loop back to the pin where MAIANA expects the AIS TX switch. This blows up an ESD protection diode on the MacArthur HAT. The tricky thing is, to apply a fix that's not interfering with the functionality of MAIANA. Increasing the working voltage of the ESD diode from 3.3V to >12V is my current favorite.
Meanwhile, people that already have a MacArthur HAT can make their own dummy plugs by cutting off the connector from an old network cable.