TS-7970 Errata
From embeddedTS Manuals
| Issue | Status | Description |
| RS232 prevents booting on REV A | Workarounds available, fixed in REV B |
Early TS-7970 REV A boards may fail to boot if RS232 is connected before the board is powered. A small amount of RS232 idle negative voltage leaks from the transceiver to the FET controlling the switched 5V. The FET will not toggle while the output has a negative voltage, so the 5V rail never comes up. If this is a concern or if the issue is seen, we can rework the board to have a 2.5ohm resistor from SW_5V to 5V_A on U47 pins 4 and 5. REV A boards shipped after 01/13/2016 include this fix. |