Texas Instruments MSC1210 - Manual (Page 168)

SPI System Errors
13-6
13.5 SPI System Errors
Some SPI systems define two types of system errors: write collision and mode
fault. Write collision is defined to occur when a byte is written to the transmit
register before the previous byte was sent. Mode fault is an error that occurs
in multiple master systems when two masters try to write at the same time.
There is no need to worry about write collision errors because the SPI transmit
path is double-buffered. However, care should be taken to assure that more
bytes are not written to the SPIDATA register before the previous bytes have
been transferred. With the FIFO operation, when the FIFO is filled, the next
writes to the SPIDATA register are ignored.
When the SPI system is configured as a master and the SS input line goes to active
low, a mode fault error has occurred—usually because two devices have at-
tempted to act as master at the same time. In cases where more than one device
is concurrently configured as a master, there is a chance of contention between
two pin drivers. For push-pull CMOS drivers, this contention can cause permanent
damage. Care should be observed to protect against excessive currents in a multi-
master system because the MSC1210 does not detect a mode fault.