Reply To: UM6-LT SPI Troubles

[Caleb Chamberlain]

Hi Eugene,

The SPI pins on the UM7 are not 5V tolerant, and operating above their absolute maximum rating could damage them (See page 10 of the datasheet, here: http://www.chrobotics.com/docs/UM7_Datasheet.pdf). The pins do have built-in ESD protection, so they may be OK. But it’s possible that the protection circuitry was burnt out, since they aren’t designed to handle sustained overvoltage conditions.

Also, make sure that the timing constraints described in the datasheet aren’t being violated. To wit,

“The maximum SPI clock rate is 10 MHz. However the UM7 needs at least 5 microseconds between bytes to copy the next byte into the SPI transmit register. For high clock rates, this means that a delay must be added between consecutive bytes for correct operation”