Sleep mode is similar to the standby mode except the SPI interface and INH typically are disabled. As the low power CAN receiver is powered off of VSUP the implementer can turn off VIO. If VIO is present in sleep mode, SPI access can take place but at a reduced rate. If at least a 10 μs delay is used between pulling nCS low and the start of a read or write the max SPI rate can be utilized. If VIO is off, the SPI interface is turned off and the only ways to exit sleep mode is by a wake up event or power cycle. A sleep mode status flag is provided to determine if the device entered sleep mode through normal operation or if a fault caused the mode change. Register 8'h52 provides the status. If a fault causes the device to enter sleep mode, this flag is set to a one.
Difference between Sleep and Standby Mode