TS-7970 Errata: Difference between revisions
From embeddedTS Manuals
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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 | 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. | ||
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Revision as of 14:41, 25 February 2016
| 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. |